Answer:
≈58.265 cm
Explanation:
first, take the full circle with diameter 20cm
the perimeter of the bottom half of that circle will equal the perimeter of the circle part/bottom part of the shape in question.
perimeter of circle = πd = 20π ≈ 62.83 cm
divide by 2 to get the bottom half ≈ 31.42 cm
next, add the length at the top right, which is 20-12 = 8 cm
finally, we have the inside circle part. to find the perimeter of this, think of a circle with 12cm as its diameter. we want to find the perimeter of that bottom half.
circumference of circle = 12π ≈37.7cm
divide by 2 to get bottom half ≈ 18.8cm
add these 3 parts together
18.8cm + 8cm + 31.42 cm ≈58.265 cm