Given:
Area of a sector = [tex]15\pi[/tex]
Radius = 5 cm
To find:
The central angle.
Solution:
The area of a sector is:
[tex]A=\dfrac{1}{2}r^2\theta[/tex]
Where, r is the radius and [tex]\theta[/tex] is the central angle in radians.
Putting [tex]A=15\pi, r=5[/tex] in the above formula, we get
[tex]15\pi=\dfrac{1}{2}(5)^2\theta[/tex]
Multiply both sides by 2.
[tex]30\pi=25\theta[/tex]
Divide both sides by 25.
[tex]\dfrac{30\pi}{25}=\theta[/tex]
[tex]\dfrac{6\pi}{5}=\theta[/tex]
Therefore, the central angle in radians is [tex]\theta=\dfrac{6\pi}{5}[/tex].
