2020 · Q68
The two sides of a triangle are 40 cm and 41 cm. If the perimeter of the triangle is 90 cm, what is its area?
Elementary MathematicsMensuration
- A90 cm²
- B135 cm²
- C150 cm²
- D180 cm²
Explanation
The third side is 90-40-41 = 9 cm, and 9^2+40^2 = 41^2, so it is right-angled with area (1/2)*40*9 = 180 cm^2. Hence option (D). The 9-40-41 triple is a Pythagorean triple, so the right angle lies between the sides 9 and 40.