A metallic sphere of radius 7 cm is melted to form a cone of height 28 cm. Find the radius of the cone.
Show answer & explanation
Correct answer: B
Explanation
Volume of the sphere = Volume of the cone
Radius of the sphere = 7 cm
Height of the cone = 28 cm
Volume of the sphere = (4/3)π × 7³
Volume of the cone = (1/3)πr² × 28
Equating the two,
4 × 7³ = 28r²
4 × 343 = 28r²
1372 = 28r²
r² = 49
r = 7 cm