Question

find the
radius of the spher whose
surface area is 154cm2 .

Answer 1

Step-by-step explanation:

Let x be radius

⇒Surface Area =154cm^2

∴4πx^2=154

⇒x^2 = 4×22/154×7

= 49/4

⇒x= 49/4

x=3.5cm

hope this will help you

Answer 2

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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$\qquad\qquad\qquad\boxed{\underline{\underline{\bigstar \: \bf\:More\:to\:know\:\bigstar}}}$

• Volume of sphere = $\sf \dfrac{4}{3} \pi r^3$

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• Volume of hemisphere = $\sf \dfrac{2}{3} \pi r^3$

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• Curved Surface Area of hemisphere = $\sf 2 \pi r^2$

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• Total surface area of hemisphere = $\sf 3 \pi r^2$