From a circular sheet of paper of radius 30 cm, a sector

From a circular sheet of paper of radius 30 cm, a sector of 10% area is removed. If the remaining part is used to make a conical surface, then the ratio of the radius and height of the cone is __

90% of area of sheet = Cross sectional area of cone
⇒ 0.9 × π × 30 × 30 = π × r₁ × 30
⇒ 27 cm = r₁
∴ height of the cone =√30² - 27²= 13.08 cm