geometry, angles between two lines Two straight lines, AB and AD, lie in the same vertical plane. AB makes an angle of 25 degrees with the horizontal, and AD makes 32 degrees with the vertical. What is the angle between AB and AD? The answer is 33 degrees or 97 degrees. I cannot visualize what this question is asking. It says both AD and AD lie on the same vertical plane, then immediately says AD makes 32 degrees with the vertical. Isn't this a contradiction? Vertical plane means it has to be at a 90 degree angle with the horizontal plane. How is it possible for AD to make a 32 degree angle with the vertical if it is already on a vertical plane...

Here is a sketch:


Horizontal = $x$-axis
Vertical = $y$-axis