Please jawab pakai cara ya

Mapel : Matematika
Bab: Lingkaran

d = 40 cm
r= 1/2d = 1/2(40) = 20 cm

L =1/2 × 3,14 × r^2
L = 1/2 × 3,14 × 20 ×20
L = 1/2 × 1.256 cm^2
L = 628 cm^2

Bangun Datar

Diketahui:
diameter (d) = 40 cm
jari-jari (r) = 40/2 = 20 cm
Ditanya:
L 1/2 lingkaran = ?

Jawab:
L 1/2 lingkaran = 1/2 x π x r x r
= 1/2 x 3,14 x 20 x 20
= 3,14 x 10 x 20
= 314 x 2
= 628 cm^2 (B).

*semoga membantu. sukses selalu ^_^