tolong dong aku nggak paham

L = 1/4 * 22/7 * 7 * 7
= 22/4 * 7
= 154/4
= 38,5 m²

Cari diameter dulu =
d = 84 : 12
d = 7cm

Luas perkarang =
L = 1/4 ×22/7 × 7 × 7
L = 22/4 × 7
L = 154/4
L = 38,5 m² (A)

Kalau boleh jadikan jawaban terbaik yah