If a triangle has a base of 10 units and a height of 5 units, what is its area?

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

Area = (base × height) / 2.

In this problem, the base of the triangle is given as 10 units and the height is given as 5 units. Plugging these values into the formula yields:

Area = (10 units × 5 units) / 2

= 50 units² / 2

= 25 units².

Thus, the area of the triangle is 25 square units, which corresponds to the first choice. This confirms that the calculation was executed correctly using the standard geometric formula for the area of a triangle, clearly illustrating why this result is accurate.