Question

A rectangle is 10 cm long and 8 cm wide. When each side of the rectangle is increased by x cm, its perimeter is doubled. Find the equation in x and hence find the area of the new rectangle.

Answer 1

Length= 10cm
bredth= 8cm
perimeter = 2(10cm + 8cm) = 36cm
​according to question...
new length - 10cm + x , new breadth - 8cm + x
so
2(10 + x + 8 + x) = 2(36)
2(18 + 2x) = 72
36 + 4x = 72
4x = 72 - 36
4x = 36
x = 36/4
x = 9cm
​so, NEW length and breadth are... 19 cm and 17cm
so area = 19cm x 17cm = 323 sqcm