tolong dijawab pakai cara

*maaf ya. cuma bisa jawab no. 2 dan

2. Kel = 2×π×r = 2×22/7×21
= 22/7×21= 22×3= 66cm
= 2×66 = 132cm
L = π×r² = 22/7×21×21
= 22/7×441 = 1.386cm
3. Kel = 2×22/7×28
= 22/7×28=22×4=88cm
= 2×88=176cm


* maaf kalo salah *
!!! JADIKAN JAWABAN YG TERBAIK YA !!!