How do you physically measure the angles of a triangle on a spherical plane?

Question

Do you measure with a protractor, etc.? This is for a non-euclidean geometry homework assignment.

Answer 1

I assume you meant to ask "How do you physically measure the angles of a triangle on a SPHERE?"  I suggest measuring the arc length associated with the angle and dividing it by the radius of the sphere, to get the angle in radians, which you can easily convert to degrees.  Measure the arc length with a flexible cord that does not stretch.  Divide the arc length by the radius of the sphere in the same units to get radians.  

 

A protractor works on a flat surface, which is not the case in this problem.