Sebuah kerucut apotemanya 10 cm dan jari-jari alasnya 7 cm tentukan luas dan volumenya

Tinggi = √10^2 - 7^2
Tinggi = √100-49
Tinggi = √51
Tinggi = 7,14cm

L = L alas + L selimut kerucut 
= (22/7 × 7^2)+ (22/7 × 7 × 10)
= 154 + 220
= 374 cm^2

Volume = 1/3 × luas alas × tinggi
Volume = 1/3 × 22/7 × 7 × 7 × 7,14
Volume = 1/3 × 154 × 7,14
Volume = 366,52cm^3

Kalau boleh jadikan jawaban terbaik yah.

s = 10 cm
r = 7 cm
t = akar [s^2 - r^2]
= akar [10^2 - 7^2]
= akar [100 - 49]
= akar 51
= 7,14 cm
L = L alas + L selimut kerucut
= [phi × r^2] + [phi × r x s]
= [22/7 × 7 × 7] + [22/7 × 7 × 10]
= 154 + 220
= 374 cm^2
V = 1/3 × L alas × t
= 1/3 × phi × r^2 × t
= 1/3 × 22/7 × 7 × 7 × 7,14
= 366,52 cm^3