Maths-
General
Easy

Question

If the angles of triangle are in the ratio 1:1:4 then ratio of the perimeter of triangle to its largest side

  1. √ 3 plus 2 colon √ 2
  2. √ 3 plus 2 colon √ 3
  3. √ 2 plus 2 colon √ 3
  4. space 3 colon 2

hintHint:

First we will find the angles of the triangle and then we will use the sine rule to find the ratio of perimeter to the largest side.

The correct answer is: √ 2 plus 2 colon √ 3


    Step1: Finding the angles of the triangle.
    Let the ratio of the angles be 1 x comma 1 x comma 4 x and we know that sum of all the angle of a triangle is 180 degree
    Let triangle be A B C with angle A equals x,angle B equals x and angle C equals 4 x and the Side opposite to angle A comma angle B comma angle C be a comma b comma c respectively.
    x plus x plus 4 x space equals space 180 degree
    =>6 x equals 180 degree
    =>x equals 30 degree
    So, the angles of the triangles are
    x equals 30 comma x equals 30 space and 4 x which is 120 degree
    Hence, angle A equals 30 degree,angle B equals 30 degree and angle C equals 120 degree
    Step2: Finding the ratio of the sides
    We know that the sides opposite to the greatest angle will be the greatest. So, side c will greatest.
    We have to find fraction numerator a plus b plus c over denominator c end fraction
    By using the Sine Rule we get,
    fraction numerator sin open parentheses A close parentheses over denominator a end fraction equals fraction numerator sin open parentheses B close parentheses over denominator b end fraction equals fraction numerator sin open parentheses C close parentheses over denominator c end fraction
    fraction numerator sin open parentheses 30 degree close parentheses over denominator a end fraction equals fraction numerator sin open parentheses 30 degree close parentheses over denominator b end fraction equals fraction numerator sin open parentheses 120 degree close parentheses over denominator c end fraction
    =>fraction numerator 1 over denominator 2 a end fraction equals fraction numerator 1 over denominator 2 b end fraction equals fraction numerator square root of 3 over denominator 2 c end fraction
    This can be rewritten as
    =>1 over a equals 1 over b equals fraction numerator square root of 3 over denominator c end fraction
    By flipping the ratios,
    =>a equals b equals fraction numerator c over denominator square root of 3 end fraction
    =>from here we get a equals fraction numerator c over denominator square root of 3 end fraction and  b equals fraction numerator c over denominator square root of 3 end fraction
    =>Now fraction numerator a plus b plus c over denominator c end fraction equals fraction numerator begin display style fraction numerator c over denominator square root of 3 end fraction end style plus begin display style fraction numerator c over denominator square root of 3 end fraction end style plus c over denominator c end fraction
    =>fraction numerator 2 over denominator square root of 3 end fraction plus 1
    =>fraction numerator 2 plus square root of 3 over denominator square root of 3 end fraction

    card img

    With Turito Academy.

    card img

    With Turito Foundation.

    card img

    Get an Expert Advice From Turito.

    Turito Academy

    card img

    With Turito Academy.

    Test Prep

    card img

    With Turito Foundation.