How to Calculate the Area of a Surface

By Contributing Writer

Determining the area of a surface is important if it needs to be covered with fabric or paint or roofing. Here how to determine how much material is needed.

Calculating the Area of a Surface

Find the surface. Figure out what shape it is.

Calculate the area of a rectangle by taking the length of the surface and then multiplying it by the width of the surface. If an object had a width of 4 feet and a length of 11 feet then the total area of the object would be 44 square feet. The measurement for area of any item is in square units.

Determine the area of a triangle. Measure the base of the triangle as well as the height of the triangle. The height of a triangle is the distance from the base to the top angle at a 90 degree angle Multiply one half the height by the length of the base to get the total area.

Use these two formulas to determine the area of most shapes that have straight edges.