Area of Irregular Figures (Jump to: Lecture | Video )

Figure 1.

Above we have an irregular figure.

To find the area of an irregular figure, first split the figure into more manageable objects that you’re already familiar with.

Figure 2.

Here, we've split the figure into two rectangles and a half circle. We know how to find the areas of all these objects.

First, we find the area of rectangle 1:

Area of Rectangle 1 = Base * Height = 4 * 10 = 40

Next, we find the area of rectangle 2:

Area of Rectangle 2 = Base * Height = 3 * (8 - 4) = 12

Last, we find the area of the circle. Because it's a half-circle, we multiply the area by (1/2).

Area of Circle = (1/2)(3.14)r^2 = (1/2)(3.14)1^2 = 1.57

We add the three areas together to find our total area:

Total Area = 40 + 12 + 1.57 = 53.57