Which expression computes the area of a triangle with base 8 and height 5?

• A. 8*5
• B. 8+5
• C. (8*5)/2
• D. 8^2/2

Answer: (C)

The area of a triangle is half the product of its base and height. This comes from combining many triangles with the same base and height, which fit into a rectangle of area base×height, making the triangle occupy exactly half of that area. So you use base×height divided by 2. With base 8 and height 5, that’s (8×5)/2 = 40/2 = 20.

The other expressions don’t reflect the triangle area formula: 8×5 would give the area of a rectangle with the same base and height, not a triangle; 8+5 adds lengths, which isn’t an area; and 8^2/2 uses the base squared, which isn’t how height factors into the area.