A circular disc of radius 6 cm is divided into three sectors with central angles 90°, 120° and 150°. What part of the whole circle is the sector with central angle150°? Also, calculate the ratio of the areas of the three sectors.

θ_{1} = 90° θ_{2} = 120°, θ_{3} = 150°

Radius of circle = r = 6 cm

Area of circle = πR^{2}

⇒ Area of circle = π×6^{2}

⇒ Area of circle = 36π → eqn2

Also, Area of sector (θ_{3}) = 15π cm^{2}

Area of sector (θ_{2}) = 12π cm^{2}→ eqn3

Area of sector (θ_{1}) = 9π cm^{2}→ eqn4

Ratio of three sectors ∷ 9π:12π:15π

Ratio of three sectors ∷ 3:4:5

54