Answer: A) around 80 cm
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Explanation:
The perimeter around the circle, aka circumference, is found through this formula
C = 2*pi*r
That's for a full circle. However, we're dealing with semicircles here, so we cut that in half to get pi*r to represent the curved distance around half the circle.
For the outer larger semicircle, that curved distance is exactly 14pi
For the inner smaller semicircle, that curved distance is 7pi, since 7 is half of 14.
The total curved portions is 14pi+7pi = 21pi
Then we add on the last straight line portion that's 14 cm long to get a total perimeter of 21pi+14
This is the exact perimeter in terms of pi.
The last thing to do is replace pi with 3.14 and simplify
21pi+14 = 21*3.14+14 = 79.94
This value rounds to 80
