Answer:
A. 5 < AC < 10
Step-by-step explanation:
If ∆ABC is a right angled triangle, we use the Pythagoras formula:
c² = a² + b²
Where c = longest side
When given sides AB, AC and BC, the formula becomes:
AB² = AC² + BC²
Where AB = Longest side
In the question,
AB = 10 and BC = 5.
10² = AC² + 5²
AC² = 10² - 5²
AC² = 100 - 25
AC² = 75
AC = √75
AC = 8.6602540378
Therefore, the expression that is always true = A. 5 < AC < 10
