Answer:
Explanation:
Use Pythagorean Theorem
a^2 + b^2 = c^2
Find the Hypotenuse of the whole triangle
20^2 + 15^2 = c^2
c = 25
Cut c in half and we get x
x = 12.5
Now use Pythagorean Theorem again to find a, you can use 20 or 15 as the hypotenuse and x as the missing side, since x is in the middle.
a^2 + (12.5)^2 = 15^2
a^2 + 156.25 = 225
a^2 = 68.78
a = ~8.3