Jika luas permukaan bola 8.8704 cm2 panjang jari jarinya adalah

V = 4 phi R^2
88704 = 4 22/7. R ^2
R ^2 = 88704 x 7/4 x 1/4
R^2 = 7056
R = 84 cm

Lp= 4π[tex] r^{2} [/tex]

⇔ 8,8704= 4π[tex] r^{2} [/tex]
⇔ 8,8704= 4(3,14)[tex] r^{2} [/tex]
⇔ 8,8704= 12,56[tex] r^{2} [/tex]
⇔ [tex] r^{2} [/tex]= [tex] \frac{8,8704}{12,56} [/tex]
⇔ r= √0,70624203821656050955414012738854
⇔ r= 0,06690940117116033738596360523438 ≈ 0.07 cm = 0,7 mm