A triangle has sides of length 5, 12, and 13. What is the area of the triangle?

This is a right-angled triangle because $$5^2 + 12^2 = 25 + 144 = 169 = 13^2$$. The area of a right-angled triangle is $$\frac{1}{2} \times \text{base} \times \text{height}$$.

Ответ: $$30$$