An illustration of composite rectangle with lengths a, b, and c with area ac + bc. This illustration represents the product of c(a+b).
Claude Irwin Palmer Library of Practical Electricity: Practical Mathematics For Home Study (New York: McGraw-Hill Book Company, Inc., 1919) 272
2400×1012, 137.0 KiB
1024×431, 22.9 KiB
640×269, 14.6 KiB
320×134, 5.9 KiB