Mathematics
Grade-8
Easy

Question

What should come in place of both x in the equation
fraction numerator x over denominator square root of 128 end fraction equals fraction numerator square root of 162 over denominator x end fraction

  1. 12
  2. 14
  3. 144
  4. 196

hintHint:

We use cross multiplication to simplify the given expression and find the solution of x.

The correct answer is: 12


    GIVEN-
    x / √128 = √162 / x
    TO FIND-
    Value of x.
    SOLUTION-
    x / √128 = √162 / x
    ∴    x * x = √162 * √128 …............... (Cross multiplication)
    ∴       x2 = √ 20736 .......................... (√m * √n = √mn)
    ∴       x2 = √(144 * 144)
    ∴       x2 = √144 * √144 ................... (√m * √n = √mn)
    ∴       x2 = 144 ................................. (√m * √m = m)
    ∴      x2 = 12 * 12
    ∴      x2 = 122 ................................... (m * m = m2)
    ∴        x = 12 ..................................... (Taking square root both the sides)
    FINAL ANSWER-
    Option 'b' i.e. '12' is the correct answer to the given question.

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