The amount of surface of an object is called its area. Area is represented in units squared, for example a sheet of paper is 93.5 inches².

You can visualize how area is measured by dividing what you are measuring into small squares of the units you are measuring into. For example, a standard piece of paper is 8½ inches wide and 11 inches tall. If you put squares that are 1 inch tall by 1 inch wide on the paper and count the number of squares needed to cover the paper you are measuring the area. In the image below there are 88 whole squares and 11 half squares. The total number of squares is 93.5 squares.

Area of a Square

Area = side²

To find a square’s area, just square one of its sides.

Area of a Rectangle

Area = length x width

To find a rectangles area, simply multiply its length times its width.

A = 7 x 4

A = 28 yards²

Area of a Triangle

Area = ½ x base x height

To find a triangle’s area, you need to know the length of its height and its base. Multiply the base times the height and then multiply that by ½ (or 0.5).

Multi-shape Objects

In the video below I calculate the area of a rectangle and square together. Notice that it is much easier to calculate the area of the triangle as one triangle rather than using the Pythagorean theorem and finding the area of the two triangles, as it seems they are suggesting you do by how they label the measurements.

Area of a Circle

Area = π x radius²

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  • Monica

    Thank you so much it really help me to get a better understanding of the math.

  • Monica

    On the area of a circle i don’t understand where the 3.14 comes from can someone please explain? I want to get a better understanding of it.

    • Cherish L. Jordan

      3.14 represents pi or 22/7 for a more accurate answer. You use pi when dealing with the radius, circumference, and diameter of a circle or sphere.

  • Kiddie

    I don’t understand the part in “Area of a Triangle” where 50x.5=25 rather than 2.5…I dunno how I got that wrong 🙁

    • Kiddie

      Never mind I forgot about the 0…thank you 🙂

  • Stacy Kolenda

    How do you figure out the diameter of a circle if you only know the area? Here is the problem…..area of circle is 855 square inches. What is the diametsr of the circle? Please help

  • ryan

    here we are assuming π value as 3.14…. i hope now that’s clear to u

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