Question
In the given figure, ABC is an Isosceles Triangle in which AB = AC, then
![](data:image/png;base64,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)
- AD < AC
- AE > AC
- both 1 and 2
- none of these
The correct answer is: both 1 and 2
Related Questions to study
In
then
A =?
In
then
A =?
In the figure, AB = BC = CD = DE = EF and AF = AE Then
A = ?
![](data:image/png;base64,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)
In the figure, AB = BC = CD = DE = EF and AF = AE Then
A = ?
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAALwAAAB7CAYAAADOpOqnAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAAFxEAABcRAcom8z8AACBlSURBVHhe7Z2JV1XnucbvWu1/0XVX7+rtWl2raXvb3qaNMc3U27SZYxKNiTFxyqAGReIU5xjFIWrigBgcUMEBQUFFUXECnBVxQHAAAUEGkXmW4bn7t8uxSBCBcw5yON+zsheRwzlsznn2+z3v877fu/9DBgZeBEN4A6dRXl6uK1euKDExUbm5uc3f7ZkwhDf4EZqamtTY2Kj6+nrdu3fv/lFXV2cfLf+dn5+v+Ph4rVq1Sj/88IOSkpKaX6VnwhDe4AFA9oqKCqWnp+vkyZM6fPiwDh48qJiYGO3atUuRkZH21/DwcJvgM2fO1NixY/X1118rKipKGRkZza/UM2EIb/AAiOwFBQU20VeuXKkFCxZo4cKFmjdvnvz9/TVjxgyNGTNGb7zxhn7729/qiSee0MCBAxUaGmo/j+f3ZBjCGzwAB+FjY2O1fPlyLVq0SIGBgVq7dq02bdpk//8nn3yiX/7yl/rJT36iJ598UmvWrNHNmzebX6FnwxDe4AEgaUhCk5OT7SiPPkeXnz59Wjt37rQvAAj/zDPP2KQfOXKkMjMzm5/d82EIb/AjNDQ0qKqqSqWlpSorK1NRUZHOnj1rSxvky+DBg/XFF19o2LBhWrp0qQoLC5uf2fNhCG/QLpA3+/bt0+LFizV58mRNnDhRU6ZMsZNUvsdjXBieAkN4gzaBJZmXl6eIiAj5+flp+PDhtitDpEez48zw72vXrtn2pKfAEN7gRyBxRbvj0EBsIjpJK8Wl6upqLVu2TO+++67tzFRWVtq631NgCG9wHw6HJiEhQbNnz9ZHH32kr776SgcOHFBJSYlN7Lt379qy5rXXXrN9d0+DIbzBfdy+fVsbN27UqFGj9Nlnn9k+/IkTJ2ySA5LZS5cu6csvv9TQoUNtF8fTYAhvoOLiYtt2RJtTVPr0009tv7111RS35siRI5o/f76dsF68eLH5Ec+BIbyXAw1+6NAhu4L68ccf23qdohMJKxG9Je7cuaNTp07Z7QVE957eKNYWDOG9GBSXgoODbbvR19dXc+bMsfU6iWlboMcmOzvbrqrSNFZTU9P8iOfAEN4LQVHp+vXrdusAUR3NTttAWlpauxajo4uSw5OcmZYwhPcyUDmlWDR16lS7RQA3BoniSe0BzsAQ3kuA/CCC09oL2QcNGmRXS9m04UmFI2dhCO8luHDhgr7//ns7quPErF+//n4hyZtgCN/LgbdOIoqV6OPjo3HjxtkVUpJOb4QhfC8FSSW++bZt2+wWXgpFtASwi4nve2rS6SwM4Xsh2G967tw5m+CjR4+2LUcKSfS10xTmzTCE70WgUEQbAMWhb7/9Vu+//77d/IUrw/exE70dhvC9CFiL6HN0+ueff27r9qNHj97vhTEwhO8VYAMGLszq1attstO7/t133yk1NbX5JwwcMIT3cCBjiOK08Q4ZMkSzZs2y23YZs+FN/npHYQjvCjTWqK6sQHey0pR+NcWKrClKvnJFyZcvWkeSzl9K1aXr+bpdXKN7zU9xBSD19u3bbbKPGDHCJjszZNiEbdA2DOGdRpMVZktUkXlGl/dt1JagAH0XEKygDWGKCN9iHaEK3hiu9RHHdSwlX0XWjztrCBK5qZrS+EVUx3KkkER/DH0yBg+HIbzTsOjbWKWaW3FKi5yhuRN8NcBnhRYE79fp0yd15vQJ7Y+K1vZNe3Q48boyG5pU2/zMrgAPff/+/XZnI/46mzE2b97sMXNhHjcM4V2F4hMqi52k6WNG67kRm7XqQE7zA1JZ5g1dTzihy1fTlWURvisxmKhO/zmzYRy9MPSux8XF2b67QcdgCO8qlJ5S1dHJmj72C/11eLjWHi1qfsBaAyruqiAtT3l5ZaqwFoSu0JPe9SVLlti9MER1hpeeOXPG7n406DgM4V2FsjMqj5um2b6f6tn3V8h/w0ml37ism8lHdDYxUcdSa5RV3PyznQC7jI4fP24Xkhh8xACkLVu2KCfn3yuIQcdhCO8qlJ9TRdxUzf3iAz318kSNnL5G4ZtWKXzFFC0NXK9lh0t0ppP9WhSMdu/ebZP8gw8+sEkP+bkITNW0azCEdxXK/kX4OT4f6ek3Z+nLheE6tG+bDm5bqOCNW/XDoVKd6+AWUHrX6VNn0BHyBRnDTEe+561NX66CIbyrYEmairjpmu3noxeHb1RAdLqqq++qpvKKMm9eVdLVKmXlN6nBCswP4yxkxlZ09MJ8+OGHdvMXs9iZF2OSU+dhCO8qlJ9V9bGZmj1xvP4+Okohx1vOW6zQvbJC3cmvUP7dRlU+ZO8zupxeGKI6vetsv2OHkidOB+ipMIR3CRrUWHBE+bt85DdssP733eXy33JeeUWFlg4vUF76Bd1MOqqzF28oMbtBha18SaI6hSSGIDEAiYlftPYy9MhoddfCEN4VaKxQ3fUIJa0YoMH/eF7/1ddHQ6avVdSBPdoXs0Obli9V4JwlWr3zuA7fbVJhi5Z0/HWGILG/lDHUkyZNsiXM1atXVVvrTInKoC0YwrsCjZWqyziq5Ah/LZoyQZ+M/07+gWHaHbtX+/dv16aVQVr17QaFHb6o5Abrx3mKFbmpjiJZvvnmG3tcxoQJE+zedYYjGbgHhvAugSVpakpVWZit21kZSsvI0a3cOyosuquiojvKz8nV7ewC3S2rFlumG9RkSxgm8tL05dh+R3HJFJLcC0P4bkZ1eZliDxzQ3Llz7ekB9K9jPzJBwMD98F7CN9SpvrpCVZUVqqisUVVNveobGq3Y6z6fu6y0xCL7ftuF4dYx3PKRGY1s4DDJaffASwlfo9qcZKWdilX8oVjtO3pOx5IydSPrjoqtCFzV0ODSvnWAhKH/hcm8jLZjzN2xY8c86nYxvQFeRvh61RVlK+/KMZ2J3andO8K1PXKHtu2O0c49h7QzMlaH4xOVWlgmaOiKWE97AE1ebL+D7NiO2I/GW3888CLCN6mhOkM3otdo2/xZWhgYrrXxN5SUnqWM7PO6dDRMQd8s1vx5mxSdnCPo6KzIYO467bz0wvTv399u62W+uiH744P3EL4qUyWXNitkho9GDZmsacEJir1NDRQUqTI9TnuXr9TKRZu0K/mWuBVAVye40ALADJiQkBDbV+/bt69+97vf2f3rZqPG44XXEL4pfbdS1n+q0cNG6mXfCG04nqsyi9H/ki1WLK8q0t2kRF09najLd4pF821XdDyDjrgzBi4M0wNIUCkoQfp33nlH69at061bt5p/2qC74SWEb1D5seXaN/EZ9Rv4hf658LJibz54dwsbNVVqrCxV2b06sQ26jZ9oF8xrZPQ0NxjAX/f397cLS2h2Oh5ffPFFezgSCauxIR8PvITw95S7Z55Ch/1Ob74/Rv1XZyouu/khF4AJvEwQ4J6mODADBgywux0d9zDNysqy75/ErR779Omjt99+275hGO0DnngXDU+G9xA+2l8bh/xWb3xgEX6NRXgXqQr0OpsyiOZIGLocmSBw+fLl+946X2n5Rd48++yzeumll2y3hlu5c5c8g+6D10ia0pOB2vfVs5aOHqGXZp7SrmttpKT3atVQXaWa+gYxwuhRtiSRe+/evXYvDO0BkJ3Gr7bmwnBvJCYNvPHGG3Z1lZuIOe7AwURf48d3D7yE8E2qz96j1JBP9PmAj/TCR8FaFXdbD0xcbLin2vzbKrISyryKKpVY32rPlmTuOi0BEB3i0gtDtGb7XVvgxr5cGNiTGzZssItORHg2eYwfP94eoGTgfngJ4S3Upqn88maFzh6nkYPHaeKCYAXHxOnw8bM6m3RRly5eVtK5y0pOydStsmrRwtUW4bmTHRKGu2lQSGI2TEBAgN341R7ogGTeI8nsjh077B1MRHbcHFwcR6ekGXzqXngP4VWvppoc5R7fqKhFvvpqnJ9GT16ouUvXaW3oVm2L2qtdcZd1+kaxiqobf+TQoMMZghQfH2+PtsNi5Bbs3OOUe5o+avsdySkzH5EyXCBs7iDqp6Sk2K4N7g0Tf5FI3nYbmu6EFxG+GeVpyr+wR7GR4doUtke79scp7vgpnT5/SRfSC5RVbEmbNvxIJvHSHsC8dZJTIjNkJ+J3BI7btgcFBdmkR+s7ngvply5dao/Ng/RMEissLLQfM3AtvI/wNprUZEVsSNhgfSV6NzY2yfrvRyAKUzXlDhoQne13RGhmsXd2ggArxJ49e+xWA3Y4tSxAkQDTH0+kJy/A4sTXN1MKXAsvJXzHgO6mkOSYuU47L9N6b9y40fwTnQMXGI1k7G5Cy+PDtwRtB7QjkASTzLIaIJcMXAdD+DZAsQhSk1zioJBUMoo6ISHB6X2mkBxCs1JAfi6ClmAVQNIgb7gwKFjxnNY/Z9A1GMK3AmSnaLRgwQK99957tgvDaDt0dkf1entAunDxIGuQN7gyrWUL1ibJK1VbbEz0PRegIb3zMIRvAebCREdH24SkGkrvCw6KK28wAJmZPUPiimQhkW2LyA45xYXBCsMFePbsWTPJwEkYwlsgqlMJ5Z6mSBgiO4QngaRI5ErHhBk0SBl8/GnTptlW5cNIjD2JDcptJ+nDmTdvnk16c9ODrsMQ3gKFJMhEfws96zgyRHlIxhBTKqps0XMFiObodPpt0PEQvz0CE+mxPzkvx0x4NpGY29p0DV5LeHQz1U4iKOQmmiMf0M7sVCJBRUo88cQTev3117VixQq7+9FVRSHcnjfffNOO8vy+R4FVgR1TbP7mOdwFhAvHoHPwWsJj92EBOrz1xYsX25HTIV9o92ViLxfCq6++ajd90ejlqgm+EBbpxI6ojAz2V7UPVgHqAWh5zpcRH7hIpkDVOXgd4elKZLQdMgUHhijOnTVa39MU94QRGlRUIRg97kgeCEej18OaxDoK+mjIF4jaNJJ11AHifqxciNiWkN7c36lz8CrCEyW5p+n06dNtAkMYNlnT+di6FwatjRVIhyPkYsQGd82D9DwPSxFJ1FXw2rQqUMxCzyOXOgISXAiOw0PxiruC4NXzNxg8Gl5DeHx0CMsmDPpViKxsv2uvD50oj32IbqaTEQ8dcrIy+Pn52a0ArAxdkTiM1CNZpkeeLYGsJp0BFwz7Y/lbkGXkGOylNWgfvZ7wRHWiJ3465Xqql8gZLgDsyPaAQ4J7w2pAsxcbtJEeYWFhdlGIiimvRaGqs1YhFwm+//z58+08YevWrc2PdAz0/9BrQ/JLso2bRB7ChWC8+oejVxMewhKZSQzR6rT1UjXlAuhIVKalF7lAFCWaO3Q7ROXeS0gjiI/Lg65/1AXUGhATkr7yyiu2vOkKSL4pUNFPzwVNUxo5ikHb6JWEh0j45hR1IALleWQDyWFnIjG6PjY21k5cISb3RHUkl0R7/g3B0NFYhfxsZ5u9IDp+PzumsCcd+2A7A+QRksjxt5J34Ca5ohWit6FXEh6JQf8JUR0yknCibztbrIF8NG6h24nmaOaWhEb/U/lkAgHJLCvBpk2bOjXympWCfAD3xxmSci5cgJAduxMHiBzB4EH0KsIzwg4JQ0SGgBy4Gc4MPoJIRG5uLkaVE3++NZBIXFRoeiQOc2g66rrQS+Oo7NJj48z9V1mRuAAdiTarGlKrvcTc29ArCO/YfkdiCcmJcLgfFJJwWroiExzguRR82JTBasHq0RrIG4iK60MCSRKKa4J9yGPtgcIRFynbBbEonR3QhJxjfy37Z5FKXKid2ZnV2+HxhIeQSAHHBmlkBXqbCQKuagO4fv26fSEhkdpLCLm4yBuQE1wgrDScR3vDlrggICgjPnh95te4ArwmBSpe03HrS1OV9WDCO6I6BEH/sqkaPxqbDmnjTFRvDfx3oi/EiYmJaTda4tRwTjhD2Jloavp1ONeHnRNFIzoimUiGfHLFuTtsT/ILR5UYN4fvufK98TR4LOH54EgQkRCU/iEk0sAdW+KoqJKwUqwigX3UDiScIEjP3BkiPRu/ibAPG5PNxYAEIxrTooxb44p+HYAvT8GN86Bi7O3DXD2O8Dgg9JNg5yEDKLhAFnS2u4Cfj6WJbCJi01bQkZmQXBiOvhf2xZLMtlUYwj3i4mVVICKTyHbW028PXEDUESi6kVhTW6BC7Mrf4SnwKMITVbHecB9ITPGdKSThubtzKCkSANlBpKStAFelI0kgrgmdkLgvRHmIzwXQOvGFeDST0RuPW0MXpKudFVYXJA3nT189ti0JsqtWEk+BxxAexwNZAMkd9zTFFemuRAxS8vvJFSBlZwjJxYJUcUw/YEVC17NyOECbAO0FaG3aDZxpTHsYOGfaIpCBOE5MOKbPvuV59Hb0eMJDNLxvtCeRCX/Zsex39wfF5pC33nrLthAhaEfBCgHZWJ3oqSeJpIkN0rdcmaiW8vch1UiU3QHkE4kxThL2KU4Sq4u3yJseTXj0OoUTyvckXbgkEL9173p3gV1QWJ8QHlnS2SYtZBDVT1wl5A3EdiSpgNyExJXf4c4bJnDx4c2ThPO+0mNEwt+ZCrGnokcSHu2LDKDszodCfwgamA/lcc5dhOR0T9JmwHSDrtycjDwEecb0MvIQkki8eyQM7Q+QD+lD3767VzAiO0k4KycRH8uVWsLjBu/Rowp2XUWPJDytuxSP0OokWbgjRMbHvYcTK5SIjCyh3birzhCJIm4NySyanSiL60TUJSHm9dl+SMHLnUklK865c+fs9xpNz3vNDirGCz4u8Pdy0WGduqM67ELC88HgTTepoRHdan+zUyABxf5z7NskwYMIrpoY4Cz4AM6fP29HeVYcNL0zQFpAMEjP6G2iLS4OKwj9MMi57igSIZ+4gB0BhuS5I/ts3QEIz/mQXGPjsspTrWZVdMWK5zrCN1VJNZm6W5CjtJwaFXQySBC9kQk0X1FxRLcT8ZAN7lreOgvIx3lCSvpU+ECcBRc5PT9IGRJWCIeOR8YR5dsrcLkKJKwEFX6fo4WCpjtn9+12FTTA8fnDAyY7sKUSS5jvd2TCQ3twHeErb6k+OUQHI0O0OCJV+5NrH3nLGIBeJ1lj5xB/GFHG4Rz0FKK3BtGQTRvID1dIDkjNxe3o8nzyySf161//2rYNeX+6C+RNkJ6LDomDG/Y4DAImMzM9mRUPNwsLmhWP94f3hMIZxT8kX2fdJZcRvunOOeWGfyH/0YP10sgQ+e/Ktm8b8zA68CGzRKEhmRqARYaW5Q3nje+pZAdMIyMak1u4KgpCbHQ9JHvuuef0q1/9yt5U4g4/vj3w9zhGepNUcz5YpN1pW7KSYk4g+dDy2LcEFwIi41L69etn7yEgB4I/5FZEfp7zKAnoIsJXq/L2ISWsHKrP//as+vT11ZiAY0qstQJ/80+0BpqME+bqJaJQVqe8zvcd4KLgje4pB9GcC5GCF81eLLt8GMgS3mgea+t5jzocsoXXoL7AHQEJADhU6Fden9d25/vBBedYrZCRFNkgFfYphTBWXDx8fo5z4Wtbr+OKo/WqSRILsWkMZHUlh6J4R/8UVXfOk3OkzvEone884ZusSFyXrvz0PdqyfonGvztQnz33lny+3qA16fXKbBWo+VD5A0iMKOL85je/sbUaZXWWdZqu8Ls5eay5nnRAPs6LzR7UBPDLWWZpBcBFgvxtPa8jB68Lqfgd5AZ4/URZGtB4fV6b96Wt57rq4Bz4O/g9WMCYB88//7z+9Kc/2dICwpFvuPvz4bU5+JsdB2YG7w/8wCxAFcCfX/ziF/rZz35mcwgZ9Khdbc4T/l6FlBGr9FMRCo5O0HL/eVo97B/y8Zstn8h8nWhVkOQKppzNcv3000/bWvXll1+2CUREY1cRby5XbU878Kr5iqNCUklCRSQm0eYxZ88bkvP38/9oaCQFG7N5fV67O94X/g5WW5Jo8okXXnjB/oz+/Oc/24k6soLz7K7PiN/D74Mb2LVEd86N9//nP/+5fvrTn9pBk++zB+BROY/ThG+sKlDRgVU6smaBloQdUlDwMoVO/D8N6j9C/zc5XlsvVqnlKUB4rD0SD3pSSEZYjogmLFMkKnztiYfj3IjqHEgPvrZ8zJnD8Rp8eER23hN+R+uf646D38vnwgHZuOioDCMjHJKiOw5+F9Gc94MLgLGHv//97+2jb9++dmTHNYPsHcn7nCZ8XfFVJa63Muevxst/RZACNy7Uqpn99c7f3laffku1aH+66L52pBLoM/xskjGSDRJUNCNfSVA84WC0NufLwd/Q1s84c/D6vCcc7nj9jhyOv5H9BZwDuVW6dfAY/86xHudnHjhavYYrDhJmagJoeKxSCP7HP/7RjvAksnwfLhFIOwInCV+g2tyj2rthg5YvDFX47oNKOHNAcXsD5D9koD54ebi+XHdMB0ok9zXvGvRmOMYjkqyy0mAWIG3IJ7ggOosuEt7KohuqVZttaffDAVq9ca8Cdufrap6V7dff073yFJ1d+pnm9Pur3h23UlMOlCql2MrsnbesDR4bGtXU8C9npramxjqqVV1dparKKlVWWv9f1yB3GMlMf8ANY2Q5uRO2NRH/UVr9Yegi4evUWHpd13bMU8iUEfJbuFXfnqhT5v1VJVf528Zo2Zv/rT881V9/8dut4DMFyrUeN5z3QDTW6F5xurKTj+nEof3av3ef9sfG6sDBWMVE71b0zhjFnkzRpYJ7KnEx6x3zPNHwDL51tuWh64QvTtHlbSu0fsZ0zV8TrS1XK5XtuOga8lV6Ikg7Zw3WxwM/14ApWxR84rayDeEfAevdaapTfXWZSu8WqDA3R3k5aNlMZWRmKfOWpeuLqlTujlDaHhqrVHc3VSn7ghQ6d5xmzZyr2UE7tC4iShGb1yls9VIFbzugyEuVSnNxhzGShsor+YQrqtpdJLy1vNWVqiTrhm5eTtbVDCuxqWxQteN8mmrVUJKl/GuJOnc6UacuZuhmYbWq3N8H5eGw3qD6EpVnXdDlw5HavSlYG6zoFhwSqpDNW7U5bKeiDifpVEa57nZf4dP6POvVWFuqjJil2jLmJY32nS7fsHTtuZKtW2mnlHUyRPv3xSr8ZLmSO74vpkNwFPtcBSeT1l4GK7reqyhUYfZNZVxL0bXUFKWkXlHylRQlJ6cpLbtYViriRlgRo75MlWkHdXHLTM2d4KuPfRfpm4At2h4VqajtG7V+5XKtWLlRG/df0OnbdS6XEO0hP3a5Ikc/pZF+czXukHTBXtErpNLzykhN1tlr1brVw+/CYwh/HxbZGitUnXtBqYc2K2L1ci1dsUarNmxVWESEwsK2a8feY4pPLVBWRaPqnV9d20ZTgxrzjqgg0lcTR43W8yO3aGVMmopLClWSc1wJQRPkP7Sf3h85T+O3XtfJ2/XdJhPzDwYoaswzGun7tcbsLtXxfCtRrbKkVw72bLHKrSX8XnfLrU7CEP4+LNo01agu/5xu75mjZV+N1oBRSzQ1MEbxJ+N1ImGrtq1epm8XbNCaqEQlFdbJbRMb78arfK+vvhzloz4jd2n9ccdvuqOCsz8oem5/ffDKB/rH8HUKOGppfOuRrnkWnUPBkR8UNbavRgwZoffmRyogLELRuyK0fmeK4pKr7d0QPR2G8K1RdkWNcdO1bPInemZosGaGZ1speo11MZzXmZBpmvBafw0ZtVQrk0p0zV05yd0ElcaM1yQfXz03ykoOj7YQxo2pKkr8XosGvaVXnxohn6Bjiq2yhEU3hPk7R4OsCN9HQwcO0GsTlmvmYn8tW/atpgckKCyhVJXdcdU5CUP41qhMlU7M0PIpn6nP0BDNjnSMASlVZsx8zf/n03qvv58mHSjQ8c7d9KPjsAhfEjNBk8f46vlR27XuSMu9s2VqLNiprT5v6sP//YcGzd2t9dnWU9weXptUcHiVFeGf0aefjtGQwARtOhynE/Ex2r73ohIuFKnaAwothvCtUXlVOvWNAqcO018HLpLv8nhdTbuq9OQExayeoWkD3rOStu+1/EyJrFXcPWiX8NWqKz6kXZPe1sinXtDAmZFaecPS192gJ+4cDtTuL1/QmMkLNPFgnRKxIOuKVZhbqDsF5apnb2cPhyF8a1Rdtwg/R0GTBqrPP8foPd8VCgkJVOiSsfpy6EC9/u5U+S47qri8OlW4i2QPEH6Hgo+2nJdZpprCaG0b97aG/+UVfey/x47whd0QXPMPrrAi/LMaPX6u/PbV6WxzatHUUK+G+ga5wCZ3OwzhW6MSwn+jHyYP0tNvTNLH00K1K3qL9mycpBkj+umVV0ZpyNdRirxWpgJ3NQgVn1BF7GRN9RuvF312KfR4C6+vKU3lF5fo24/e0st9R2rc6pOKL7eu0+aH3YMGNVblKXXTJC3t9wv9881henvlVUVdt7IbDyB5SxjCt4ZD0kz/XM8NCdK00KsqripRVXmiTgVP0NTXnrGivK9Gb76mIznu+LSb1FRwRIW7xsrvs5HqM3yzAvdlqLaW/pUqVd2M1qVNPvIdNEyvDFmjgEMZyrOUhHt5d0/1RVd0fv14zX/3D3r59aEasPi4wi5VqswTrJkWMIRvjapr0tm5WjV7rF4cGaaF0f8eTFSTuE5Rn/6P3v77q3p+VrzWJ7nBlmisVF3qViUtfUsDXvqb/vPFqRq1MEJH4g7o6P5wbQuYqcUTv9DYqYGaE3FNZ3KrusEObFBDZa5yzsfoaFiQQkIjFZ6Qrku5tar2sOq5IfwDaFRTcZKqYydo/pj39Yd3Fmts4GndKryjosJcpcUGaavPcxo8YJDeWnhCWy+54X6oDaWqSYnUqcDPNfbjQfr7h7Pkt2C9tkWEKHzD91oyZ46+nrtWa2OSdaH44XuG3Q8P0zLNMIR/AHWqzzyotOCP5Nuvr37+1Ai96hOozTsitHfHGivq+2rc+wM1zG+x5h24pfNFboitTbWqL85UfupJnUmIU2y8JaUupOr6DetISdL5c0k6e4HepBqzx6ALMIR/ABbhc04rbfcCBcwYq2Fj/TVpUajCdoRrz/ZVCvpuvr6Zs1qBO87p3J169f7Ro70PhvAPwJI0teWquput25lpup6WpZu38pRfkK/Cgmzl3MpSRlaB8oqrbe3qmYu6d8MQ3sCrYAhv4FUwhDfwKhjCG3gVDOENvAqG8AZeBUN4A6+CIbyBV8EQ3sCrYAhv4FUwhDfwIkj/D95YmKIa72uPAAAAAElFTkSuQmCC)
In the figure, AB = AC,
and
Then
![](data:image/png;base64,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)
In the figure, AB = AC,
and
Then
![](data:image/png;base64,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)
In the figure,
and
are two exterior angle measures of
ABC Then
is
![](data:image/png;base64,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)
In the figure,
and
are two exterior angle measures of
ABC Then
is
![](data:image/png;base64,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)
How many days are there from 2nd Jan 1983 to 15th March 1983 ?
Therefore, number of days between 2nd Jan 1983 to 15th March 1983 is 72 days.
How many days are there from 2nd Jan 1983 to 15th March 1983 ?
Therefore, number of days between 2nd Jan 1983 to 15th March 1983 is 72 days.
At what time between 1 A.M and 2 A.M will both hands of a clock point in opposite directions ?
The time is minutes past 1 o'clock when the both hands are in opposite direction.
At what time between 1 A.M and 2 A.M will both hands of a clock point in opposite directions ?
The time is minutes past 1 o'clock when the both hands are in opposite direction.
Ramu can complete
of the work in 5 days and Ravi can complete
of the same work in 6 days How long would both of them take to complete that work, if they work together ?
Therefore, to complete the work, It takes 12 days if they work together.
Ramu can complete
of the work in 5 days and Ravi can complete
of the same work in 6 days How long would both of them take to complete that work, if they work together ?
Therefore, to complete the work, It takes 12 days if they work together.
If A, B and C can finish a piece of work in 12 days, 15 days and 20 days respectively If all the three work at it together and they are paid Rs 960 for the whole work, how should the money be divided among them ?
Therefore, the money should be divided in the ratio of 5:4:3
i.e, A's share=400
B's share=320
C's share=240
If A, B and C can finish a piece of work in 12 days, 15 days and 20 days respectively If all the three work at it together and they are paid Rs 960 for the whole work, how should the money be divided among them ?
Therefore, the money should be divided in the ratio of 5:4:3
i.e, A's share=400
B's share=320
C's share=240