Answer:
15 units
Explanation:
For this question, we must use the pythagorean theorem to solve. This theorem can be used to find the missing length of right triangles.
a^2 + b^2 = c^2
Let's fill in the lengths that we know
a^2 + 12^2 = 13^2
Solve
a^2 + 144 = 169
a^2 = 25
a*a = 25
Find the square root of 25
5
The length of the second leg is 15 units
Hope this helped :)