The sum of interior angles in a triangle is 180°. To prove \(a + b + c = 180^\circ\), firstly draw a line parallel to one side of the triangle. \(d = b\) (alternate angles are equal ...

Plot a graph of angle of incidence, i in o on the y-axis against angle of refraction, r in o on the x-axis and draw the line of best fit. We can see from the graph that as the angle of incidence ...