Mensuration Practice Test 7

Perimeter of the rectangle = 2 (l + b) = 82
l + b = 41
b = 41 − l
Area of the rectangle = l × b = 400
l × (41 − l) = 400
41l − ${\mathit{l}}^2$ = 400
${\mathit{l}}^2$ − 41l + 400 = 0
${\mathit{l}}^2$ −16l − 25l + 400 = 0
l(l −16) − 25(l −16) = 0
l = 16, 25
not possible
l = 25
breadth = 41 − l ⇒ 41 − 25 = 16 cm