1. Keliling alas sebuah kerucut 44cm dan panjang garis pelukisnya 25cm. Hitunglah: a. Panjang jari-jari alas b. Luas kerucut c. Volume kerucut

s = 25 cm
Keliling = 44cm

a. Keliling = 2×phi×r
44 = 2×22/7×r
44 = 44/7 × r
44 ÷ 44/7 = r
44 × 7/44 = r
7 = r
r = 7 cm

b. Luas = phi×r×(r+s)
= 22/7 × 7 ×(25+7)
= 22 × 32
= 704 cm^2

c. t = akar (25^2 - 7^2)
= akar (625 - 49)
= akar 576
= 24 cm

Volume = 1/3 × phi × r^2 × t
= 1/3 × 22/7 × 7^2 × 24
= 1/3 × 22/7 × 49 × 24
= 1.232 cm^3