Question

The length of a rectangle is four times its width. The perimeter is 100 cm. What is the number of square centimeters in the area of the rectangle?

Answer 1

Explanation:

let width=x

length=4x

2(x+4x)=100

2×5x=100

x=100/10=10

width=10 cm

length=4×10=40 cm

area=l×b=40×10=400 cm²

Answer 2

let width be 'x'

according to the question,

length = 4x

perimeter = 100 cm

we know ,

perimeter of rectangle = 2(l+b)

100= 2(4x+x)

100= 10x

x= 10

then length = 4x = 4×10= 40

and , area of rectangle = l×b

= 40 × 10 = 400

area of rectangle is 400cm