What is the height of a rectangle with an area of 40 and a base of 10?

To determine the height of the rectangle, we can use the formula for the area of a rectangle, which is:

Area = Base × Height.

In this scenario, we have the area as 40 and the base as 10. By substituting these values into the formula, we can solve for the height:

40 = 10 × Height.

To isolate Height, we divide both sides of the equation by 10:

Height = 40 / 10, Height = 4.

Therefore, the height of the rectangle is 4. This makes choice C the correct answer, as it accurately reflects the calculated height based on the given area and base.