Answer for Day 7 Math Problem
6.75π square meters 🎯
21.21 meters² 🎯
Any of the two answers above shall be accepted.
Solution
The formula for the surface area of a sphere is 4πr². Since a hemisphere is just the half of a sphere, its (outer) surface area is 2πr². Since the hollow part of the hemisphere is covered, there is an additional πr² on the surface area of the hemisphere. Therefore, we just need to get the radius by halving the diameter, then substituting it to 3πr² to get the final answer.
- radius = (diameter) / 2 = 3 / 2 = 1.5
- surface area = 3 * π * 1.5² = 6.75π square meters or approximately 21.21 meters²
Winner: @minus-pi 🏅
1 HIVE has been sent to @minus-pi's Hive account. 💰
Sorry for posting the problem late! I know that most of the participants are in locations where it is almost midnight at the official time of 03:00 P.M. (UTC +8). This problem came from one of my draft problems which I archived because I liked more the other problems I prepared. 😅
- @jfang003's answer would have been correct, if he didn't forget to divide the diameter by 2 first!
- I don't know how @appukuttan66 got his answer.
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Special mentions: @dbuzz, @chrisrice, @jancharlest, and @mehmetfix 🤯