Answer: The third side has a length of 25 units.
Step-by-step explanation:
In a right triangle, we can use [tex]a^2+b^2=c^2[/tex] to find the side length of c.
[tex]15^2+20^2=c^2[/tex]
225 + 400 = 625
[tex]\sqrt 625[/tex] = 25
Therefore, c = 25.
I hope this helps!
