tolong bantu ya kak.....

a. L = π × r × r
22/7 × 21 × 21
1368cm²
b. K = 2 π × r
2 × 22/7 × 21
132cm.
c. Panjang busur LM = besar sudut LMN/ 360° × keliling lingkaran.
= 60°\360°× 2 πr
= 1/6×22/7×21
= 22°
:) Semoga membantu:)