Answer:
x = 3.75
Step-by-step explanation:
ABC is a right angled triangle.
Therefore, by Pythagoras theorem:
[tex] {(10 - x)}^{2} = {x}^{2} + {5}^{2} \\ 100 - 20x + {x}^{2} = {x}^{2} + 25 \\ 100 - 20x = 25 \\ - 20x = 25 - 100 \\ - 20x = - 75 \\ x = \frac{ - 75}{ - 20} \\ \: \: \huge \red { \boxed{x = 3.75}}[/tex]