tolong di jawab yaaa pake cara

Lpersegi - Ldaerah arsir
30×20 - 446
600-446
154

Llingkaran = phi.r^2
154 = 22/7 . r^2
154× 7 /22 = r^2
1078 /22 = r^2
49 = r^2
7 = r

Diamater = 2r
= 2 (7)
= 14 cm