# The perimeter of a rectangle is 20 cm. The width of the rectangle is 4 cm. What is the area of the rectangle?

Sep 10, 2015

The area is $24 c {m}^{2}$

#### Explanation:

Let $a$ and $b$ be the sides of the rectangle.

The width $a$ is $4 c m$,
If perimeter is $20 c m$ then we can write $2 a + 2 b = 20$

$a + b = 10$

$4 + b = 10$

$b = 6$

Now we can calculate the area: $A = a \cdot b = 4 \cdot 6 = 24$

Answer: Area of this rectangle is $24 c {m}^{2}$