Question

a rectangle is 10 centimetre long and 8 cm wide when each side of the rectangle is increased by X and its perimeter is double find the equation and X and hence find the area of the new Triangle

Answer 1

In the first rectangle,
l=10cm and b=8cm

therefore perimeter = 2(l+b)
= 36cm

therefore, if the length and breath are increased by Xcm,

2(l+x+b+x)=36 × 2

2l +2b +4x = 72

substuting l and b,

20 + 16 + 4x = 72

4x = 72 - 36

x = 36 ÷ 4

x = 9cm

Area of new recrangle = L × B

= 19 × 17
=
${ 323}^{2}$