tolong dijawab nya guys,,,,

a. 1/4 phi.r^2
1/4.22/7. 14^2
154cm^2
b. 3/4 phi r^2
3/4 3,14 10^2
235,5 cm^2

a. luas = 1/4 × phi × r × r =
1/4 × 22/7 × 14cm × 14cm =
1/4 × 22 × 2cm × 14cm = 154cm2
b. luas = 3/4 × phi × r × r =
3/4 × 3,14 × 10cm × 10cm =
3/4 × 314cm = 78,5cm2
maaf kalo salah