sebuah kerucut mempunyai diameter 10cm dan volume 314cm³ jika π= 3,14 maka luas permukaan kerucut adalah..

dik : d = 10 cm
r = 1/2.d = 1/2.10 = 5
phi = 3,14
V. kerucut = 314
dit : L.p. kerucut.....?
V.kerucut = 1/3.phi.r^2.t
314 = 1/3.3,14.5^2.t
314 = 1/3.78,5.t
1/3.78,5.t = 314
1/3.t = 314/78,5
1/3.t = 4
t = 4: 1/3
t = 4× 3/1
t = 12
s^2 = r^2 + t^2
s^2 = 5^2 + 12^2
s^2 = 25 + 144
s^2 = 169
s = akar 169
s = 13
L.p.kerucut = phi.r (r + s)
= 3,14 .5 (5 + 13)
= 15,7 . 18
= 2826
semoga membantu.....