If a rectangle has a perimeter of 40 the length is 8 what is

If a rectangle has a perimeter of 40, the length is 8, what is the width and the area? 5. If a triangle has an area of 22, and the base is 4 what is the height?

Solution

1) half circle has radius = 5

area of half circle = pi*r^2 / 2 = pi* 5^2 / 2 = 39.25

perimeter of half circle = pi*r = 3.14 * 5 = 15.7

2) perimeter of rectangle = 40

length = 8

perimeter of rectangle = 2( l+w ) = 40

2 ( 8 + w) = 40

8 + w = 20

w = 20 - 8 = 12

area = 12*8 = 96

5) area of triangle = 22

base = 4

therefore , height of triangle

1/2 * base * height = 22

base * height = 44

height = 44 / base = 44/ 4 = 11