Problem about angles(1)



problem

In the right figure,l is parallel to m.
(1)When the angle a=30degrees,b=45degrees,find the angle APB.
(2)When the point P is between the line l and m,find the expression for the angle APB using a and b.
(3)When the point P is above the line l,find the expression for the angle APB using a and b.

Drag red point.