If a triangle has a base of 8 cm and a height of 5 cm, what is its area?

To find the area of a triangle, you can use the formula:

Area = (base × height) / 2.

In this case, the triangle has a base of 8 cm and a height of 5 cm. Plugging these values into the formula gives:

Area = (8 cm × 5 cm) / 2 = 40 cm² / 2 = 20 cm².

This calculation confirms that the area of the triangle is indeed 20 cm², making the choice of 20 cm² correct. The formula effectively accounts for the fact that a triangle is half of a rectangle with the same base and height, leading to this specific result.

Other options either miscalculate the area or apply an incorrect value for the base or height, thus leading to results that do not accurately reflect the triangle's dimensions.