Volume suatu kerucut 770 cm3.jika tinggi kerucut 15 cm dan v=22/7,hitunglah panjang jari-jari alas kerucut tsb !

770 = 1/3 x 22/7 x r^2 x 15
770 x 3 x 7/22 : 15 = r^2
49 = r^2
r = 7

V = 1/3 phi r² t
770 = 1/3 22/7 r² 15
770 = 110/7 r²
r² = √245
r = 7√5