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A quarter sphere with a radius of $10 \text{ units}$.
Please help, also remember the sides.
I used the normal formula of the total surface area of a sphere and divided it by $4$, then added half the area of a circle but it wasn't equal to the correct answer.
1 Answer
$\begingroup$Let's first try to imagine the quarter of the solid sphere:
It has a curved surface and $2$ mutually perpendicular plane surfaces
$$\text{T.S.A} = \underbrace{\frac{1}{4} 4\pi r^2}_{\text{curved surface area}} + \overbrace{\frac{1}{2}\pi r^2 + \frac{1}{2}\pi r^2}^{\text{Plane surface surface}} = 2\pi r^2$$
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