45
Step-by-step explanationA right-angled triangle is a triangle, that has one of its interior angles equal to 90 degrees, to find the missin angle we can use the fact that the sum of the internal angles in a triangle equals 180 degrees, so
Step 1
given

so
![\begin{gathered} sum\text{ of internal angles =}180 \\ replace \\ m\measuredangle BCA+m\measuredangle CBA+m\measuredangle CAB=180 \\ 45+90+m\measuredangle CAB=180 \\ 135+m\measuredangle CAB=180 \\ subtract\text{ 135 in both sides} \\ 135+m\operatorname{\measuredangle}CAB-135=180-135 \\ m\operatorname{\measuredangle}CAB=45\text{ \degree} \end{gathered}]()
therefore, the answer is
45
I hope this helps you