Can you help me with this?

Answer:
11
Step-by-step explanation:
apply pythagoras theorem
Answer:
11.2 cm
Step-by-step explanation:
By Pythagoras Theorem:
Length of diagonal
[tex] = \sqrt{ {10}^{2} + {5}^{2} } \\ \\ = \sqrt{100 + 25} \\ \\ = \sqrt{125} \\ \\ = 11.1803399 \\ \\ \approx 11.2 \: cm[/tex]