The easiest formula to use to find area is the handy length times width for a rectangle, however, irregular shapes don't come with that luxury, in this lesson you will learn how to make finding the area of irregular shapes easy as cake! As seen in figure 1, we are trying to find the area of the red triangle. To make our jobs easier, we created a rectangle sounding it, using right triangles. To find the area of this, you need to calculate the area of each of said triangles (the green ones) To find the area of these all you have to do is half of base times height. For triangle CAD, it would 1 times 2 divided by 2, which means the area for it is 1. Triangle CBF would be 3 times 1 divided by 2, which is 1.5. See if you can guess what Triangle AEB would be
Triangle AEB would be 1! Now for the finding the area of the rectangle we created around the original triangle, it is length times width. The length from C to F is 3, and the length from D to C is 2. 3*2=6. For the last step, subtract the areas of Triangles AEB, CAD, and CBF from 6. In this case it would be 6-1.5-1-1. This is 2.5. The area of triangle ABC is 2.5
Try some practice problems to increase your skills!