Question

A cone is 8.4cm high and the radius of its base is 2.1 cm.it is melted and recast into a sphere. Find the radius of the sphere.

Answer 1

volume of cone=1/3*πr^2 h
volume of sphere =4/3πr^3
4/3πr^3=1/3πr^2h
4r^3=2.1*2.1*8.4
r=2.1

Answer 2

HI there !!

Height = h = 8.4 cm

Radius = r = 2.1 cm

Volume of cone = 1/3πr²h

Volume of the cone = Volume of new sphere

Volume of new sphere = 4/3πr³

4/3πr³ = 1/3πr²h

4/3 × 22/7 × r³ = 1/3 × 22/7 × 2.1 × 2.1 × 8.4

4 r ³ = 2.1 × 2.1 × 8.4

r ³ = [ 2.1 × 2.1 × 8.4 ] ÷ 4

r³ = 9.261

r = ∛ 9.261

r = 2.1 cm