Question

Jari jari alas kerucut = 12 cm t = 9 cm hitunglah
a panjang garis pelukis
b luas selimut
c luas seluruh isi kerucut

Answer 1

A)
garis pelukis (s)
s² = t² + r²
s² = 12² + 9²
s² = 144 + 81
s² = 225
s = 15 cm

b)
luas selimut = πrs
3,14 x 12 x 15 = 565,2 cm²

c)
luas kerucut = luas alas + luas selimut
πr² + πrs
(3,14 x 12 x 12) + 565,2
452,16 + 565,2
1017,36 cm²

Answer 2

S = akar 12 kuadrat + 9 kuadrat
= akar 144 + 81
= akar 225
= 15 cm

l selimut = phi r s
= 3.14 x 12 x 15
=565.2

v = phi r kuadrat + phi r s
= 3.14 x 12 x 12 + 3.14 x 12 x 15
=452.16 + 565.2
= 1017.36 cm kubik