A triangular sail has a base length of 2.5 centimeters. The area of the sail is 3.75 square meters. How tall is the sail?

The area of any triangle = (1/2) x (length of the base) x (height)

2.5 centimeters = 0.025 meter

The area of the sail is (3.75) = (0.5) x (0.025) x (height)

Multiply each side by 2 : (7.5) = (0.025) x (height)

Divide each side by 0.025 : (7.5) / (0.025) = height = 300 meters

The situation is stupid, but the math is bullet-proof.