Geometry
Slant height
Pythagoras on the triangle from the base centre, up the height, and out to the midpoint of an edge.
The Formula
l = sqrt((half base)^2 + h^2)
Pythagoras on the triangle from the base centre, up the height, and out to the midpoint of an edge.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| l | Slant height | metres | Distance up a triangular face from edge midpoint to apex. |
| b | Base dimension | metres | The base side measured across to that face. |
| h | Height | metres | Perpendicular height of the pyramid. |
What Each Symbol Means
lmetres
Slant height
Distance up a triangular face from edge midpoint to apex.
bmetres
Base dimension
The base side measured across to that face.
hmetres
Height
Perpendicular height of the pyramid.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate the volume of a pyramid page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate The Volume Of A Pyramid, filed under Math. Every number the guide produces comes from substituting into this one line.