Angles Used to Illustrate Sum and Difference of Two Angles Small 320×320 Medium 640×639 Large 1024×1023 Download TIFF Original 2400×2397 | (237.9 KB) Description Angles used to illustrate the sum and difference of two angles and trig identities. Keywords angles, coordinate axis with angle, drawn, identities, perpendicular, Right Triangle, sum and difference, terminal side, triangles, trig, trigonometry, x-axis, y-axis Galleries Trigonometry: Angles Source: Claude Irwin Palmer Library of Practical Electricity: Practical Mathematics For Home Study (New York: McGraw-Hill Book Company, Inc., 1919) 455