Figure out the kind of angle you are working. A right angle is formed by perpendicular line segments and is 90 degrees. An obtuse angle is bigger than a right angle. An acute angle is smaller than 90 degrees.
Pose the intersecting points of the cross. An intersecting point is the center location where two distinct lines cross one another. These are your two line segments. Every line segment must extend and cross both axes. Make sure that the initial start is to the left and underneath the left intersecting point.
Resolve the slopes of the two lines by measuring the rise of the line segment. Divide it by its horizontal aspect. You'll need to use two points on each line. Once that is completed, carefully measure the divergence between the vertical components. Now divide the difference within the horizontal component. This will provide you with the ratio, which will always be the slope of the line. You've just determined angles without using a protractor.