- #1
MHB This is the formula for finding the area of a circle, where r is the radius.
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To find the area of a circle, the formula A = πr² is used, where r is the radius. In this discussion, the focus is on calculating the area of a larger semicircle from which two smaller semicircles are removed. The areas of the smaller semicircles are each one-fourth that of the larger semicircle due to their linear dimensions being half. The combined area of the two smaller semicircles is half of the larger semicircle's area. The final calculation provided estimates the area as approximately 154 cm².
- #2
I like Serena
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MHB
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susanto3311 said:
Hey! ;)
It looks like a big half circle from which 2 smaller half circles are removed.
Let's start with those.
Can you tell what their radius's are? (Wondering)
- #3
MarkFL
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Another approach would be to utilize the concept of similarity. The two smaller semi-circles have linear measures that are one-half that of the corresponding measures of the larger semi-circle, so we know their areas must each be one-fourth that of the larger. Since there are two of them, we then know the combined areas of the two smaller semicircles is one half that of the larger. So, find the area of the larger, and cut it in half (divide by two) and you will have the area in question. :D
- #4
- #5
MarkFL
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You want to find half of the area of the semi-circle...it appears you have found the area of the semi-circle...
edit: nevermind...it was unclear at first that you have divided by 2 twice...you should only use the equal sign to equate 2 quantities that are equal. :D
edit: nevermind...it was unclear at first that you have divided by 2 twice...you should only use the equal sign to equate 2 quantities that are equal. :D
- #6
susanto3311
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could you make more simple?...
- #7
MarkFL
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More simple than finding half the area of a semi-circle? No. :D
- #8
susanto3311
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how about...
= 308/2 = 154 cm2
it's true...??
= 308/2 = 154 cm2
it's true...??
- #9
MarkFL
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I would write:
$$A=\frac{1}{2}\left(\frac{\pi}{2}(14\text{ cm})^2\right)=49\pi\text{ cm}^2\approx154\text{ cm}^2$$
$$A=\frac{1}{2}\left(\frac{\pi}{2}(14\text{ cm})^2\right)=49\pi\text{ cm}^2\approx154\text{ cm}^2$$
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