The formula for the area of a triangle is given by:

Here are the solutions for the areas of the given figures.

a)

Step 1: The formula for the area of a triangle is given by:

$$A = \frac{1}{2} \times \text{base} \times \text{height}$$

Step 2: Substitute the given values for the base ($7 \text{ cm}$) and height ($8 \text{ cm}$).

$$A = \frac{1}{2} \times 7 \text{ cm} \times 8 \text{ cm}$$

Step 3: Perform the multiplication.

$$A = \frac{56}{2} \text{ cm}^2$$

Step 4: Simplify the expression.

$$$$