If a triangle has base b and height h, its area is which expression?

• A. (1/2) b h
• B. b h
• C. (1/2) b + h
• D. b^2

Answer: (A)

Area is measured as base times height, but for a triangle you only get half of that rectangle. Visualize a rectangle with the same base and height as the triangle. Its area is base times height. If you draw a diagonal across the rectangle, it splits into two equal triangles, so each triangle has half of that area. That gives the triangle’s area as (1/2) × base × height, or (1/2) b h.

The other forms aren’t correct for a triangle: bh would be the area of the rectangle with the same base and height, not the triangle. Adding the base and height, (1/2) b + h, mixes lengths and doesn’t yield an area. And b^2 is the area of a square with side b, unrelated to the height.