Area of a triangle, a rectangle and a circle can be calculated as follows. For a right angle triangle with one angle of 90 degrees the equation is area equals one half times the base. Times the height. Let’s look at an example. If the base of this triangle is 4 centimeters and the height is 8 centimeters. Let’s substitute these numbers into the equation. Area equals 1/2 times the base, 4 centimeters, times the height, 8 centimeters, which equals 1/2 times 32 centimeters squared.

Which equals 1 times 32 is 32 over 2, which equals 32 divided by 2 in your calculator. Equals 16 centimetres squared. Now let’s calculate the area of a rectangle. The equation is area equals length times width. Let’s look at an example.The length of this rectangle is ten centimeters. And the width is 5 centimeters. Let’s substitute these numbers into the equation. Length Of 10 centimeters, times the width of 5 centimeters. Put these numbers into your calculator and press equals. Your final answer will be 50, centimeters squared. Now let’s calculate the area of a circle. The equation is area equals pi times r squared. Let’s look at an example. If the radius, the r, of this circle is 3 centimeters. Let’s substitute this number into the equation. Area equals pi, which is represented by 3.14, times 3, the radius, squared. Which equals 3.14 times 9.

Put these numbers into your calculator and press equals. The final answer will be 12.14 centimeters squared..