Geometry
Slant height
Pythagoras on the right triangle formed by the radius, the height and the sloping edge.
The Formula
l = sqrt(r^2 + h^2)
Pythagoras on the right triangle formed by the radius, the height and the sloping edge.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| l | Slant height | metres | Distance up the curved surface from base edge to apex. |
| r | Radius | metres | Radius of the base. |
| h | Perpendicular height | metres | Vertical height. |
What Each Symbol Means
lmetres
Slant height
Distance up the curved surface from base edge to apex.
rmetres
Radius
Radius of the base.
hmetres
Perpendicular height
Vertical height.
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 cone 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 Cone, filed under Math. Every number the guide produces comes from substituting into this one line.