Answer: 10mm
Step-by-step explanation: First you have to set up an equation using the formula: (a squared)+(b squared)=(c squared), (24 squared) + (x squared)=(26 squared
Then, solve for x: (26 squared)- (24 squared)= 676-576=100
Lastly, find the square root of 100, which is 10!
Hope this helps and I would appreciate it if you marked me as brainliest, but u don't have to!