Answer:
13
Step-by-step explanation:
The given triangle is a right-angled triangle
The missing side can be found by using the Pythagora's theorem
The hypotenuse, H = 85
The adjacent, A = 84
The opposite, O = ?
According to the pythagora's theorem:
H² = A² + O²
85² = 84² + O²
7225 = 7056 + O²
O² = 7225 - 7056
O² = 169
O = √169
O = 13
Therefore, the length of the missing side in the right triangle is 13