Oblique Triangle for Distance Across a River Small 215×320 Medium 429×640 Large 687×1024 Download Tiff Original 1609×2400 | (454.4 KB) Description Illustration of oblique triangle used to find distance across a river. Keywords Distance, Lake, law of cosines, law of sines, proportion, proportions, river, stream, triangle, triangles, trig, trigonometry Galleries Trigonometry: Triangles Source: Claude Irwin Palmer Library of Practical Electricity: Practical Mathematics For Home Study (New York: McGraw-Hill Book Company, Inc., 1919) 466