Skill: Calculate the area of triangles

To find the area of a triangle, use:

$$A=\frac{1}{2}bh$$

Here:

• $b$ is the length of the chosen base.
• $h$ is the perpendicular height to that base. The height must meet the base at a right angle; it is not always a slanted side.
• The answer is written in square units.

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

1. Identify the base and height:

$$b=8\text{ cm}, \qquad h=5\text{ cm}$$

2. Substitute into the formula:

$$A=\frac{1}{2}(8)(5)$$

3. Multiply:

$$A=\frac{1}{2}(40)=20$$

4. Write the answer in square units:

$$\boxed{20\text{ cm}^2}$$

The area of the triangle is $\boxed{20\text{ square centimeters}}$.