Question

the length of a rectangle is 4 more than 3 times the width. If the perimeter of the rectangle is 18.4cm, what is the area of the rectangle

Answer 1

A = 10.27cm²

Explanation:

Let's represent the width as x,

therefore since the length is 4 more than 3 times the width, it can be represent as 3x + 4, Perimeter = 18.4cm

Perimeter of a rectangle = 2(L + B)

`18.4= 2(3x+4+x)\\18.4= 6x+8+2x\\18.4-8=6x+2x\\10.4=8x\\x=(10.4)/(8)\\x=1.3`

width = 1.3cm

Length = 3x + 4 = 3*1.3 + 4 = 7.9cm

Area of a rectangle = length x width

A = 7.9 * 1.3 = 10.27cm²

Answer 2

Let the width be w
Length = 3w +4
Perimeter = 2*(l+b)
2*(3w+4+w)=18.4
2*(4w+4)=18.4
8w+8=18.4
8w=18.4- 8
8w= 10.4
W=10.4/8
w= 1.3 cm
L=3*1.3+4
=3.9+4
l=7.9


Area = length * width
= 7.9*1.3
= 10.27 square cm