Could someone please help me with this question? I have been struggling with it for a while.

Question

If a cone with a diameter of 10 meters has a surface area of 290.6, find its slant height.

Answer 1

Hello Giselle;

Slant height for a cone is the hypothenus of the right triangle formed. s² = √(h² + r²)

r = 10/2 = 5m

Total Surface area = Area of The circle base + Area Side = Πr( r + s )

Π x 5 ( 5 + s) = 290.6

15.7(s + 5) = 290.6

s + 5 ≈ 18.5. => s ( slant height) = 13.5 m