Question

if each side of a cube is increased by 50% , find the percent increased in its surface area

Answer 1

Hello,

Here's the answer :-

Let the side of cube = x

Original surface area = 6x^2

New side = x(1 + 50/100) = 3x/2

New surface area = 6 x 9x^2/4 = 27x^2/2

increase in surface area = 27x^2/2 -6x^2 = [27x^2-12x^2] / 2 = 15x^2 /2

Percentage increase =

[15x^2/2] / 6x^2 x 100% = 250%

Hope it helped :-)

Answer 2

let the side of cube = x
surface area = 6x^2

on increase 50% =x+ x×50/100. = 3/2*x

now sa= 6(3/2x)^2= 27/2x^2

SA.increase. = (27/2-6)x^3 =15/2x^2

% Of surface area increase = increase in SA/previous Sa ×100%

=(15/2x^2)/6x^2×100%

=125%