The area of the base of a cone is 38.5 cm² and the curved surface area is 143 cm². The slant height of this cone will be?
Answer & explanation
Correct answer: option 3
Area of base = \(\pi \)r2 = 38.5
⇒ \(\pi \)r2 = 38.5
⇒ r2 = \(\frac{38.5 × 7}{22}\)
⇒ r = 3.5 cm
C.S.A. = \(\pi \)rl
⇒ 143 = \(\frac{22}{7}\) × \(\frac{7}{2}\) × l
⇒ l = 13 cm