What is the formula for calculating the area of a triangle?

The formula for calculating the area of a triangle is defined as A = ½bh, where 'A' represents the area, 'b' stands for the base of the triangle, and 'h' signifies the height perpendicular to the base. This formula originates from the fact that a triangle can be conceptualized as half of a rectangle or parallelogram when you draw an altitude from the top vertex down to the base. By multiplying the base and height (which gives the area of a rectangle) and then dividing by two, you arrive at the area of a triangle.

The other options describe areas for different shapes: the formula for a circle (area = πr²), the area of a square (area = b², where 'b' is the length of a side), and the area of a rectangle (area = length × width). Each of these formulas serves a specific geometrical figure, confirming that A = ½bh is uniquely applicable to triangles.