## Triangle

While it is easy to calculate the area of a triangle when its bottom and height are known, it is interesting to resolve other three elements while 3 of the 6 elements (3 sides and 3 angles) are known.

The sum of its 3 angles is always equal to 180°, or 1 PI (π). Therefore, the third angle is known when the other 2 angles are known.

Calculations of the triangle can fill a whole textbook, which is called trigonometry.

Let's play with it!

## Circle

Area of a circle is simple to calculate: A = π/4 * D2.

However, if a circular section of a pipe filled with partial full water, it may not so easy to know its wet area, wet perimeter, which give you hydraulic radius by WA / WL = Rh. Let's use the calculator on the right to resolve it.

## Cylinder or Pipe?

Similar!

The calculator on right is capable to calculate the volume, weight with or without water in it for pipes from steel to PVC.

Do not forget to use it in your sump pit calculations, too!

More useful calculators are to come.

# Area and Volume

Decimal Point:
Triangle (bottom and height)
BottomHeightArea
Triangle (3 sides)
Side aSide bSide CArea ∠A°∠B°
Triangle (Side, Angle, Side)
Side a∠C°Side bAreaSide c ∠A°
Triangle (Angle, Side, Angle)
∠C°Side a∠B°AreaSide c Side b