pake cara y Gans hahah

Bab Bola
Sekolah Menengah Pertama Kelas VII

7. Lp = 1/2 × 4 × phi × r × r
= 2 × 3,14 × 2,5 × 2,5
= 39,25 cm2

8. Lp = r = 12 ÷ 2 = 6 cm
= 4 × phi × r × r
= 4 × 3,14 × 6 × 6
= 452,16 cm2