Posted by **Ted** on Sunday, May 30, 2010 at 11:09pm.

how do you calculate the surface area of a cone with a slant height of 13cm and a height of 12cm.?

- math -
**MathMate**, Monday, May 31, 2010 at 8:28am
To calculate the curved surface area of the cone, we need to know the base radius R.

The slant height (L) of a cone is 13 cm

The vertical height (H) is 12 cm

Use Pythagoras theorem to find the radius of the base, R

R² = L² - H²

R = sqrt(13²-12²)

=5

The curved surface area of a cone is the product πRL = π*5*13 = 65π

To this, we should add the surface area of the base, equal to πR².

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