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# perimeter of a shape with a semicircle in it. watch

1. Hi Guys,
Im trying to calculate the perimeter of the shape below. To calculate the perimeter of the semicircle i've done 'the diameter+ half the circumference' but when i add this number to the perimeter of rectangle and equilateral triangle, it gives me a wrong answer. There should be something wrong with the way i calculate the perimeter of the semicircle perhaps not adding the final answer to diameter. Any suggestion??
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2. (Original post by Alen.m)
Hi Guys,
Im trying to calculate the perimeter of the shape below. To calculate the perimeter of the semicircle i've done 'the diameter+ half the circumference' but when i add this number to the perimeter of rectangle and equilateral triangle, it gives me a wrong answer. There should be something wrong with the way i calculate the perimeter of the semicircle perhaps not adding the final answer to diameter. Any suggestion??
Could you type what you have added together please? You don't include the dotted lines as they aren't part of the perimeter.
3. (Original post by Alen.m)
Hi Guys,
Im trying to calculate the perimeter of the shape below. To calculate the perimeter of the semicircle i've done 'the diameter+ half the circumference' but when i add this number to the perimeter of rectangle and equilateral triangle, it gives me a wrong answer. There should be something wrong with the way i calculate the perimeter of the semicircle perhaps not adding the final answer to diameter. Any suggestion??
The diameter of the semicircle in the diagram isn't part of the perimeter of the shape you're investigating.
4. Thanks Guys

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