Question:
The figure is formed by 2 identical semicircles overlapping each other. The radius of each semicircle is 5 cm. O is the centre of both semicircles. AOB and COD are the diameters. The area of the shaded part OBD is 20 cm² and the perimeter of the shaded part OBD is 18 cm.
(a) Using the calculator value of π, find the area of the figure. Correct your answer to 2 decimal places.
(b) Using π = 22/7, find the perimeter of the figure. Give your answer as a mixed number in the simplest form.
Solution:
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