To find the missing side of a triangle when you have the lengths of the other two sides, you can use the Pythagorean theorem if it’s a right triangle. The formula is:
a² + b² = c²
Here, a and b are the lengths of the two shorter sides (legs), and c is the length of the hypotenuse (the longest side).
For example, if we know the lengths of the sides are 3 and 4, we can find the hypotenuse:
3² + 4² = c²
9 + 16 = c²
25 = c²
Now, take the square root of both sides:
c = √25
So, c = 5.
If you need to find a missing leg instead, say you know the hypotenuse (5) and one leg (3):
3² + b² = 5²
9 + b² = 25
b² = 25 – 9
b² = 16
b = √16
So, b = 4.
After finding the missing side, if needed, round it to the nearest tenth. If the answer was, for instance, 4.1, then you round to 4.1. But if it was 4.15, you’d round it to 4.2.