The total surface area of a hemisphere is 166.32 sq cm, find its radius?
- A4.2 cm
- B8.4 cm
- C1.4 cm
- D2.1 cm
Solution & Step-by-step Explanation
The formula for the total surface area (TSA) of a solid hemisphere is:
TSA=3πr
2
Given, TSA=166.32 cm
2
and taking π=
7
22
:
166.32=3×
7
22
×r
2
166.32=
7
66
×r
2
r
2
=
66
166.32×7
Simplifying the division:
66
166.32
=2.52
r
2
=2.52×7=17.64
r=
17.64
=4.2 cm
Hence, the radius of the hemisphere is 4.2 cm.
TSA=3πr
2
Given, TSA=166.32 cm
2
and taking π=
7
22
:
166.32=3×
7
22
×r
2
166.32=
7
66
×r
2
r
2
=
66
166.32×7
Simplifying the division:
66
166.32
=2.52
r
2
=2.52×7=17.64
r=
17.64
=4.2 cm
Hence, the radius of the hemisphere is 4.2 cm.