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A spherical balloon's radius increases steadily from 5 cm to 7 cm.
Find the increase in its surface area (take π = 22/7).

Class 9Surface Area of a SphereMensuration

A $301.71 cm^{2}$
B $616 cm^{2}$
C $314.29 cm^{2}$
D $150.86 cm^{2}$

Step-by-Step Solution

Initial SA =

4 * (22/7) * 25 = 314.29 cm^{2}

. Final SA =

4 * (22/7) * 49 = 616 cm^{2}

. Increase

= 616 - 314.29 = 301.71 cm^{2}

.

Answer: A)

301.71 cm^{2}

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