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September 29th, 2012, 03:22 AM   #1
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I have a question about the area of this shape?

Picture 1 and 3 are related to this question; Where did the nr. 15 come from?

Picture 3: How do I figure this out?

I found the area of the circle and then I found the area of the other shape and lastly added the two. (Of course, I was wrong.)
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September 29th, 2012, 03:26 AM   #2
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Re: I have a question about the area of this shape?

Quote:
Originally Posted by mathismydoom
Picture 1 and 3 are related to this question; Where did the nr. 15 come from?

Picture 3: How do I figure this out?

I found the area of the circle and then I found the area of the other shape and lastly added the two. (Of course. I was wrong.)
I forgot to attach picture 3:
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September 29th, 2012, 04:04 AM   #3
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The triangle is being assumed to be equilateral, so that half its base is 15 cm. That's how the value "15" was obtained.

Picture 3 seems to be giving an unrelated shape. I suggest you find the shape's area by adding the area of its rectangular lower portion to the area of its semicircular upper portion. Are you able to do that?
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September 29th, 2012, 04:33 AM   #4
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Re:

Quote:
Originally Posted by skipjack
The triangle is being assumed to be equilateral, so that half its base is 15 cm. That's how the value "15" was obtained.

Picture 3 seems to be giving an unrelated shape. I suggest you find the shape's area by adding the area of its rectangular lower portion to the area of its semicircular upper portion. Are you able to do that?
I did that and I didn't get the correct answer.
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September 29th, 2012, 04:40 AM   #5
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If you post your working, we can check it for you.
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September 29th, 2012, 05:10 AM   #6
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Re:

Quote:
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If you post your working, we can check it for you.
Rectangle: 0.76 * 0.52 = 0.39 m^2

Half circle: 0.0314*0.76 = 0.023

0.39 + 0.023 = 0.413 m^2

The answer is supposed to be 0.62 m^2
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September 29th, 2012, 05:34 AM   #7
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Re: I have a question about the area of this shape?

For the area of the semi-circle, you want to take half the diameter, then square it and multiply by ?/2:



Recall the area of a circle is

Then the total area is about:

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