tolong pake cara yaaaaa plisss

Luas lingkaran =
π × r²
3, 14 × 20²
1256 cm²

24. keliling belah ketupat:
diket: AB= 17 cm
AC= 30 cm
BD= 16 cm

jawab:
keliling= 4 X sisi
= 4 X panjang AB
= 4 X 17 cm
= 68 cm (c)

25.luas lingkaran:
diket: diameter= 40 cm
jawab:
r (jari jari)= 40 :2
= 20 cm
luas = π x r2
= 3,14 x 20 x20 cm
= 1256 cm2 (c)