Answer:
2.5
Explanation:
If you know two other sides of the right triangle, it's the easiest option; all you need to do is apply the Pythagorean theorem:
a² + b² = c²
if leg a is the missing side, then transform the equation to the form when a is on one side, and take a square root:
a = √(c² - b²)
if leg b is unknown, then
b = √(c² - a²)
for hypotenuse c missing, the formula is
c = √(a² + b²)