Skill: Find area of parallelograms

To find the area of a parallelogram, multiply the length of the base by the perpendicular height:

$$A=bh$$

The height must make a right angle with the base. It is not usually the slanted side.

Example: A parallelogram has a base of $8\text{ cm}$ and a perpendicular height of $5\text{ cm}$. Find its area.

1. Identify the base and height:

   • $b=8\text{ cm}$
   • $h=5\text{ cm}$

2. Substitute into the formula:

$$A=bh$$ $$A=(8)(5)$$

3. Multiply:

$$A=40$$

4. Use square units because area measures a surface:

$$\boxed{40\text{ cm}^2}$$

You can also imagine cutting off the slanted triangle on one side and moving it to the other side. This makes a rectangle with the same base and height, so the area is still $40\text{ cm}^2$.