Do you have the idea of ‘vectors’ to work with?
We can use the arccosine of dot products to find the angles.
EB had the best solution . . . elegant!
But there is a formula for this problem.
. . Given two lines with slopes and
. . the angle between them is given by: .
Find the tangents of the angles of the triangle ,
and find the angles to the nearest degree.
We have: .