See how to find the surface area/volume of a pyramid.
3 examples and their solutions.
that has a vertex, a polygon base,
and triangle lateral faces.
whose base is a regular polygon
and whose lateral faces are
all congruent isosceles triangles.
So the vertex and the center of the base
are the endpoints of the height.
Regular Pyramid: Surface Area
A = B + 12Phs
= (base area) + (lateral area)
hs: Slant height
V = 13Bh
B = 7⋅4 - 
h = 9
V = 13⋅28⋅9
B = 12⋅9⋅8 - 
h = 10
V = 13⋅36⋅10