13. diketahui diameter kerucut 10 cm dan panjang garis pelukisnya 13 cm. volum kerucut adalah…

Cari tingginya dulu
r = d/2 = 10/2 = 5 cm

t = akar ( s^2 – r^2)
t = akar (13^2 – 5^2)
t = akar (169 – 25)
t = akar (144)
t = 12 cm

V = 1/3 π r^2 t
V = 1/3 π x 5 x 5 x 12
V = 1/3 300π
V = 100π cm^3 (b)

Tinggi kerucut
= √garispelukis²-r²
= √13²-5²
= √169-25
= √144
= 12 cm

Volume kerucut
= ⅓ × Πr² × tinggi
= ⅓ × Π×5×5 × 12
= B. 100Π cm³