Area and Perimeter of a Triangle

• Diameter (d) = 2r
• Circumference (c) = πd or 2πr

To find out the triangle's area, you will need only the length of the base (b) and the height (h), which is measured from the base to the peak of the triangle. This formula works for any triangle, no matter if the sides are equal or not.

The triangle is one of the simplest shapes and calculating the perimeter of this three-sided form is rather easy. You will need to know the lengths of all three sides (a, b, c) to measure the full perimeter.

• Perimeter = a + b + c

• Area = 1/2 bh

Area and Circumference of a Circle

Similar to a sphere, you will need to know the radius (r) of a circle to find out its diameter (d) and circumference (c). Keep in mind that a circle is an ellipse that has an equal distance from the center point to every side (the radius), so it does not matter where on the edge you measure.

These two measurements are used in a formula to calculate the circle's area. It's also important to remember that the ratio between a circle's circumference and its diameter is equal to pi (π).

• Area = πr²