Question 37

loading...

Prev/Next links

waecmaths question: 

The perimeter of a sector of a circle of radius 21cm is 64cm. Find the angle of the sector. Take [$\pi=\tfrac {22}{7}$ ].

Option A: 

70o

Option B: 

60o

Option C: 

55o

Option D: 

42o

waecmaths solution: 

$\begin{align}  & Perimeter=\frac{\theta }{{{360}^{\circ }}}\times 2\pi r+2r \\ & 64=\frac{\theta }{{{360}^{\circ }}}\times 2\times \frac{22}{7}\times 21+2(21) \\ & 64=\frac{\theta }{360}\times 132+42 \\ & 22=\frac{\theta }{{{360}^{\circ }}}\times 132 \\ & \theta =\frac{22}{132}\times {{360}^{\circ }}={{60}^{\circ }} \\\end{align}$

maths year: 
maths topics: