Multiple choice

The total surface area of a solid hemisphere of radius 3.5 m is covered with canvas at the rate of Rs. 20 per $m^{2}$. The total cost to cover the hemisphere is $\displaystyle \left(Take\, \pi\, =\, \frac{22}{7}\right)$

  1. Rs. 2210

  2. Rs. 2310

  3. Rs. 2220

  4. Rs. 2420
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The total surface area of a solid hemisphere is 3 * pi * r^2. With r = 3.5 m, the area is 3 * (22/7) * 3.5 * 3.5 = 115.5 m^2. Multiplying this area by the rate of Rs. 20 per m^2 gives a total cost of 115.5 * 20 = Rs. 2310.

AI explanation

The total surface area of a solid hemisphere is calculated as 3 times pi times the square of the radius. Substituting the radius of 3.5 meters gives 3 times 22/7 times 3.5 squared, which equals 115.5 square meters. Multiplying this area by the canvas cost of 20 rupees per square meter results in a total cost of 2310 rupees.

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