Answer:
sqrt 50
Explanation:
First of all this is a square so if AB = 5, then AD is also 5.
Let's get rid of the other triangle and only focus on triangle ABD.
Using Pythagorean theorem we are able to solve this problem.
The Pythagorean Theorem basically states that:
a^2 + b^2 = c^2
Where a and b are the legs and c is the hypotenuse, aka the thing that we are trying to solve for right now.
Substitute these numbers in: 5^2 + 5+2 = c^2
Solve: 50 = c^2
c= sqrt 50
^ and that is our answer!