s² = r² + t²
s² = 4² + 12²
s² = 16 + 144
s² = 160
s = √160
s = 4√10
L = πr (r + s)
L = 3,14 x 4 (4 + 4√10)
L = 12,56 x 4 + 12,56 x 4√10
L = 50,24 + 50,24√10
L = 209,113 cm²
V = 1/3 πr² t
V = 1/3 x 3,14 x 4² x 12
V = 1/3 x 3,14 x 16 x 12
V = 3,14 x 16 x 4
V = 200,96 cm³
b. d = 12 cm, maka r = 6 cm, s = 10 cm
s² = r² + t²
10² = 6² + t²
t² = 10² – 6²
t² = 100 – 36
t² = 64
t = √64 = 8 cm
L = πr (r + s)
L = 3,14 x 6 ( 6 + 10)
L = 18,84 x 16
L = 301,44 cm²
V = 1/3 πr² t
V = 1/3 x 3.14 x 6² x 8
V = 1/3 x 3.14 x 36 x 8
V = 3.14 x 12 x 8
V = 301,44 cm³
c. r = 6 cm, t = 10 cm
s² = r² + t²
s² = 6² + 10²
s² = 36 + 100
s² = 136
s = √136
s = 2√34 cm