Geometrymedium · Past Paper
If the perimeter of a semi-circular protractor is 36 cm, find its diameter. (pi = 22/7)
A7 cm
B14 cm
C21 cm
D28 cm
✓ Correct Answer: B — 14 cm
Perimeter = pi*r + 2r = r(22/7 + 2) = r(36/7) = 36. So r = 7, diameter = 14 cm.
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