A sphere and a right cylinder have the same radius and volume. The cylinder has a height of 3 inches. Find the radius.
V sphere = 4/3 pi r^3
V cyl = pi r^2 h
4/3 pi r^3 = pi r^2 h
4/3 r =h
h=3
so: r = 3 *3 / 4 = 2.25 in
Answer:
The radius of the sphere and cylinder is 2.25 inches.
Step-by-step explanation:
It is given that sphere and a right cylinder have the same radius and volume.
Let the radius of the sphere and cylinder be r.
The volume of the sphere is
\(V_1=\frac{4}{3}\pi r^3\)
The volume of the cylinder is
\(V_2=\pi r^2h\)
The cylinder has a height of 3 inches.
\(V_2=\pi r^2(3)=3\pi r^2\)
\(V_1=V_2\)
\(\frac{4}{3}\pi r^3=3\pi r^2\)
\(4\pi r^3=9\pi r^2\)
\(\frac{\pi r^3}{\pi r^2}=\frac{9}{4}\)
\(r=\frac{9}{4}=2.25\)
Therefore radius of the sphere and cylinder is 2.25 inches.