y = 20 units
This seems to require the Pythagorean Theorem. So you’ll start with the formula: a^2 + b^2 = c^2.
Your a would be 24, and c would be 26. We’re solving for b then, so first you have to simplify.
24^2 + b^2 = 26^2 become 576 + b^2 = 676.
Then you have to subtract from both sides to isolate the unknown variable, b.
576 + b^2 = 676
-576 -576
b^2 = 100
Finally, you have to find the square root of 100.
b^2 = 100 —> b = 10
The length of the leg b, or y in your case, is 10.