To solve for \( mAD \), we'll use the properties of a cyclic quadrilateral. In a cyclic quadrilateral, the opposite angles sum up to 180 degrees.
Given the angles:
- \( mQU = 55^\circ \)
- \( mAU = 112^\circ \)
- \( m\angle UAD = 100^\circ \)
Let's label the points based on the angles:
- \( mQU \) and \( mAD \) are opposite angles in the cyclic quadrilateral.
- Thus, \( mQU + mAD = 180^\circ \).
First, we can find \( mAD \): \[ mAD = 180^\circ - mQU \] \[ mAD = 180^\circ - 55^\circ = 125^\circ \]
Now we have \( mAD = 125^\circ \).
So, the answer is: \[ mAD = 125^\circ \]