JAMB - Mathematics (2016 - No. 30)
An arc of the length 16\(\pi\)cm subtends an angle of 80o at the centre of the circle. Find the radius of the circle.
24cm
28cm
36cm
32cm
Explicaţie
L = \(\frac{\theta}{360}\) x 2\(\pi\)r
16\(\pi\) = \(\frac{80}{360}\) x 2\(\pi\)r
\(\frac{16\pi \times 360}{80 \times 2\pi}\) = r
r = 36cm
16\(\pi\) = \(\frac{80}{360}\) x 2\(\pi\)r
\(\frac{16\pi \times 360}{80 \times 2\pi}\) = r
r = 36cm