Posted by dull on .
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)b²/4
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,
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.