Question

if the T. S. A of sphere is 98.56cm^2 find radius

Answer 1

Hi ,

Let the radius of the Sphere = r cm

T.S.A ( A ) = 98.56 cm² [ given ]

4πr² = 98.56

=> 4 × ( 22/7 ) × r² = 98.56 cm²

=> r² = ( 98.56 × 7 )/( 4 × 22 )

=> r² = 1.12 × 7

=> r² = (4 × 4 × 7 × 7 )/( 10 × 10 )

=> r = ( 4 × 7 )/10

r = 2.8 cm

Therefore ,

radius of the Sphere = r = 2.8 cm

I hope this helps you.

: )

Answer 2

TSA
$tsa = 4\pi {r}^{2} \\ 98.56 = 4 \times \frac{22}{7} \times {r}^{2} \\ {r}^{2} = \frac{98.56 \times 7}{4 \times 22} \\ {r \: }^{2} = \frac{4 \times 4 \times 7 \times 7}{100} \\ {r}^{2} = \frac{ {28}^{2} }{{10}^{2} } \\ r = 2.8$ cm.
r=2.8 cm