WAEC - Mathematics (1991 - No. 18)
In the diagram above, PXR and PYO are two semi-circles with diameters 14cm and 7cm respectively. Find the area of the enclosed region, PXROY correct to the nearest whole number
96cm2
116cm2
154cm2
192cm2
385cm2
Wyjaśnienie
Area of the bigger semi circle PRO = \(\frac{πr^2}{2}\)
= \(\frac{22}{7}\) x \(\frac{49}{2}\) = 77cm\(^2\)
2nd Area of the smaller circle DYO = \(\frac{22}{7}\) x \(\frac{3.5^2}{2}\) = 19.25cm\(^2\)
Total Area = 77 + 19.25 = 96.25 ≈ 96.00cm\(^2\)