Answer:
6.4
Explanation:
The hypotenuse of a right triangle can be found from the other two sides by making use of the Pythagorean theorem. It tells you the square of the hypotenuse is the sum of the squares of the other two sides:
c² = 4² +5²
c² = 16 +25 = 41
c = √41 ≈ 6.4
The missing side length is about 6.4 units.