Geometry
Diagonal of a rectangle
Pythagoras applied to the right triangle the diagonal creates.
The Formula
d = sqrt(l^2 + w^2)
Pythagoras applied to the right triangle the diagonal creates.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| d | Diagonal | metres | Corner to corner distance. |
| l | Length | metres | The longer side. |
| w | Width | metres | The shorter side. |
What Each Symbol Means
dmetres
Diagonal
Corner to corner distance.
lmetres
Length
The longer side.
wmetres
Width
The shorter side.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate the area of a rectangle 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 Area Of A Rectangle, filed under Math. Every number the guide produces comes from substituting into this one line.