Gambar di samping menunjukkan benda terbentuk dari gabungan kerucut dan belahan bola. Dengan [tex] phi[/tex] = 3,14, hitunglah : a. volumenya, b. luas permukaan

phi = 3,14
r = 8 cm
t = 15 cm

a) V
b) Lp

a)
V = V1/2B + VK
V = (1/2 × 4/3 × phi × r^3) + (1/3 × phi x r^2 × t)
V = (1/2×4/3×3,14×8×8×8) + (1/3×3,14×8×8×15)
V = 1071,79 + 1004,8
V = 2076,59 cm^3

b)
s^2 = r^2 + t^2
s^2 = 8^2 + 15^2
s^2 = 64 + 225
s^2 = 289
s = V289
s = 17 cm
Lp = L1/2B + LSK
Lp = (1/2 × 4 × phi × r^2) + (phi × r × s)
Lp = (1/2×4×3,14×8×8) + (3,14×8×17)
Lp = 401,92 + 427,04
Lp = 828,96 cm^2