Supplementary Angles Small 320×211 Medium 640×422 Large 1024×675 Download Tiff Original 2400×1583 | (189.5 KB) Description Illustration of supplementary angles. Two angles whose sum is a straight angle. Keywords 180 degrees, angle, angles, geometry, straight line, sum, supplement, supplementary, supplements Galleries Supplementary Angles Source: G.A. Wentworth Plane And Solid Geometry (Boston: Ginn & Company, 1899) 13