Question

both questions please help

Answer 1

Answer:

area=2222.9022cm²,radius = 22.09

HOPE IT HELPS

Step-by-step explanation:

perimeter of a semicircle =72cm

$\pi$r=72cm

22÷7×r=72cm

r=72×7÷22

r=22.90cm

Area of semicircle=$\pi$r²÷2

area=22×22.90×22.90÷7×2

area=2222.9022cm²

Answer 2

Let diameter of C1 be 2x and C2 be 3x.

Now radius of C1 = 2x/2 = x

Radius of C2 = 3x/2.

Area of circle = pi r^2.

Area of c1 = pi ☓ x^2 = pix^2

Area of c2 = pi ☓ (3x/2)^2 = 9x^2/4 pi

Ar C1/ ar C2 = x^2/9x^2/4

= 1/9 ☓ 4/1 = 4/9

➡️ Ar C1 : Ar C2 = 4 :9

Que2 : Perimeter of semi circle= pi ☓ r

72 = 3.14 ☓ r

r = 72/3.14

r = 22. 92 cm

Area = pi ☓ r^2

Area = 3.14 ☓ 22.92 ☓ 22.92 cm^2

Area = 1649.52 cm^2