Question

inside of a cube is increased by 50% then what percent increase in its surface area​

Answer 1

let side of cube is a

surface area of cube S = 6a^2

so new side of the cube = a + a × 50%

= a + 50a/2 = a + a/2 = 3a/2

new surface area of cube

= 6× (new side)^2

= 6 × (3a/2)^2

= 6 × 9a^2 / 4

=( 27/2 )× a ^2

increased % = (new SA - old SA) × 100/(old SA)

=( ( 27/2 )× a ^2 - 6a ^2) × 100/ (6a^2)

= (27/2 - 6) × a^2 × 100/ (6a^2)

= 15/2 × 100 /6

= (15×100)/(2×6)

= 125 %