Posted by **dull** on Sunday, July 14, 2013 at 10:26am.

Find the surface area of a triangular pyramid with b =4 cm, h= 8.2 cm and s = 7 cm. PLEASE. How ?

GEOMETRY (SA oftriangular pyramid) - MathMate, Sunday, July 14, 2013 at 8:41am

Lateral surface area

=perimeter of base * apothem /2

=3b*s/2

(for a regular pyramid with a triangular base)

Area of triangular base with side b

=(√3)*b/2*(b/2)

=(√3)bē/4

GEOMETRY (SA oftriangular pyramid) - Anonymous, Sunday, July 14, 2013 at 10:05am

What is apothem ?

GEOMETRY (SA oftriangular pyramid) - Anonymous, Sunday, July 14, 2013 at 10:15am

why did you not include the height ?

- GEOMETRY (SA oftriangular pyramid) -
**MathMate**, Sunday, July 14, 2013 at 9:25pm
In the calculations of surface area of a pyramid, the height is not required if the apothem (slant height) is given.

The height is required, however, to calculate the volume of a pyramid.

In fact, the height h is not consistent, because h should always be less than the slant height, s.

If you could check the question for typos, there may be a different answer.

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