Question

Kerucut memiliki volume 20 cm3. Jika diameternya diperbesar menjadi 3 kali dan tingginya menjadi 2 kali, volume barunya adalah ... cm3.
a. 720
b. 480
c. 360
d. 120

Answer 1

D2 = 3d1
d2 = 3×2r1
d2 = 6r1

r2 = 1/2×d2
r2 = 1/2×6r1
r2 = 3r1

t2 = 2t1

V1/V2 = (1/3×π×r1²×t1)/(1/3×π×r2²×t2) (coret 1/3×π)
20/V2 = (r1²×t1)/(r2²×t2)
20/V2 = (r1²×t1)/((3r1)²×2t1)
20/V2 = (r1²×t1)/(9r1²×2t1)
20/V2 = 1/18
V2 = 20×18
V2 = 360 cm³

Jawaban: C