Question

Maths find the radius of a sphere whose surface area is 154cm2

Answer 1

area of a sphere = 4πrsquare.

154 = 4πr*r

154/4 = πr*r

38.5 = 22/7*r square

38.5*7 = 22*r square

269.5 = 22 * r square

269.5/22 = r square

12.25 = r square

√12.25 = r

r = 3.5

Answer 2

Step-by-step explanation:

GivEn:

• Total surface area of sphere is = 154 cm².

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To find:

• Radius of Sphere?

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Solution:

We know that,

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$\star\;{\boxed{\sf{\purple{TSA_{\;(sphere)} = 4 \pi r^2}}}}$

$:\implies\sf 4 \times \dfrac{22}{7} \times r^2 = 154$

$:\implies\sf r^2 = \cancel{154} \times \dfrac{1}{4} \times \dfrac{7}{ \cancel{22}}$

$:\implies\sf r^2 = 7 \times \dfrac{1}{4} \times 7$

$:\implies\sf r^2 = \dfrac{49}{4}$

$:\implies\sf r^2 = \dfrac{7}{2}$

$:\implies{\boxed{\frak{\pink{r = 3.5\;cm}}}}\;\bigstar$

$\therefore\;{\underline{\sf{Hence,\;the\;radius\;of\;sphere\;is\; \bf{3.5\;cm}.}}}$

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