mencari volume bola dengan panjang jari-jari 10,5 dengan 22/7

r = 10,5
π = 22/7

Volume Bola
= 4/3 π r³
= 4/3 * 22/7 * 10,5³
= 88/21 * 1157,625
= 4851

Jawaban pada Gambar, Uji Kecakapan 7 :
1) dik:
V = 352 cm³
t = 7 cm
π = 22/7
r = ...?

V = πr²t
352 = 22/7 * r² * 7
r² = 352 / 22
r² = 16
r = √16 = 4 cm

2) dik:
V = 6930 cm³
r = 21 cm
π = 22/7
t =...?

V = πr²t
6930 = 22/7 * 21² * t
6930 = 22 * 63 * t
6930 = 1386 t
t = 6930 / 1386
t = 5 cm

3) dik:
r = 7 cm
π = 22/7
V = 462 cm²
t =...?

V = 1/3 πr²t
462 = 1/3 * 22/7 * 7² * t
469 * 3 = 22 * 7 * t
1407 = 154 t
t = 1407 / 154
t = 9,136 cm

4) dik:
V = 113,04 cm³
π = 3,14
r =....?

V = 4/3πr³ 
113,04 = 4/3 * 3,14 * r³
113,04 * 3 = 4 * 3,14 * r³
339,12 = 12,56 r³
r³ = 339,12 / 12,56
r³ = 27
r = ∛27 = 3 cm