Answer:
See below:
Step-by-step explanation:
First of all, you will see that diagonal BD is a angle bisector for Angles <ABC and <ADC. Now, knowing that it is a square.
We see that the angle bisector splits the angles into 45 degrees each due to the sum of angles in a square being 360 degrees hence giving us 4 right angles.
Now, if we see this, we see that we have a 45 45 90 Triangle!
The theorem states that the hypotenuse is equal to .
Hence, we get our answer of !