Question

two semi circles are used to make the shaded shape below one semicircle has the diamiter of 12 and the other diamiter of 20 work out the preminiter of the shaded shape

Answer 1

Before finding perimeter find radius using diameter

R = d/2
= 12/2
= 6

1st semi circle = 2 π r
= 2 × 3.142 × 6. ( π is a Greek letter)
= 37.704 cm


R =d/2
= 20/2
= 10

2nd semi circle = 2 π r
= 2 × 3.142 × 10
= 62.84cm

Total perimeter = 62.84 + 37.704
= 100.544 cm