A spherical balloon has surface area 1386 cm^2 at first (take π = 22/7). More air is pumped so its radius increases by 4 cm and the new radius becomes 14.5 cm. What was the original radius?

Question

Accepted Answer

10.5 cm. From 4*π*r^2 = 1386: r^2 = 1386*7/(4*22) = 110.25, r = 10.5 cm. (Check: 10.5 + 4 = 14.5 cm, matches.)

A spherical balloon has surface area $1386 cm^{2}$ at first (take π = 22/7).
More air is pumped so its radius increases by 4 cm and the new radius becomes 14.5 cm.
What was the original radius?

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More Class 9 Surface Area of a Sphere practice

A spherical balloon has surface area 1386cm2 at first (take π = 22/7).More air is pumped so its radius increases by 4 cm and the new radius becomes 14.5 cm.What was the original radius?

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 9 Surface Area of a Sphere practice

A spherical balloon has surface area $1386 cm^{2}$ at first (take π = 22/7).
More air is pumped so its radius increases by 4 cm and the new radius becomes 14.5 cm.
What was the original radius?