Area
Area
The area of a figure tells how much space the shape takes up. You probably already know the area of a square (side times side) and a rectangle (length times width). Here are the equations to find some other common shapes' areas... 1) Triangle: 1/2 base times height (1/2(bh)), 2) Trapezoid: 1/2 height (base 1 plus base 2) (1/2 times (height times (base 1 plus base 2))), and 3) Parallelogram: base times height. When doing area problems for triangles, you need to make sure to rid of the extra space around the triangle (after drawing a box around it such as in the problem below). To do this, multiply how high and wide the box needs to go to accommodate all points of the triangle. For example, in the problem below, the area before subtracting the extra space is 56.
Triangle Area Problem
Triangle Area Solved
Next, multiply each of the three parts of the triangle that have blank space together. So, you would multiply 8 by 3, 7 by 5, and 3 by 4. Multiply each of those answers by 1/2... and subtract all three from 56! When you do this, you should get 56-(12+17.5+6), which equals an area of 20.5 units 2.
Parallelogram Problem
Parallelogram Problem Solved
This one is pretty easy. Remember, the formula to find the area of a parallelogram is simply base times height. In the case of a parallelogram, you don't need to subtract the empty space because the height isn't changing, meaning that you can go anywhere horizontally in the figure and the height is still 7 units. So, all you need to do to find the area of this figure is multiply 7 by 7, and your area is 49 units2.