Answer:
24
Step-by-step explanation:
You're given a side and a hypotenuse in a right triangle, so you're able to use the Pythagorean Theorem.
[tex]a^{2} + b^{2} = c^{2}\\\\a^{2} + (7)^{2} = (25)^{2}\\[/tex]
Now isolate a on one side and solve for a.
[tex]\\a^{2} = (25)^{2} - (7)^{2}\\\\a = \sqrt{(25)^{2} - (7)^{2}} \\\\a = 24[/tex]
