JAMB - Mathematics (2005 - No. 22)

A sector of a circle has an area of 55 cm2. If the radius of the circle is 10 cm, calculate the angle of the sector
[π = 22/7]

45^o

63^o

75^o

90^o

Area of a sector = \(\frac{\theta}{360}\times \pi r^2\)

55 = \(\frac{\theta}{360}\times \frac{22}{7}\times \frac{10\times 10}{1}\)

\(\theta = \frac{360 \times 55 \times 7}{22 \times 10 \times 10}\)

\(\theta = 63^{\circ}\)