An illustration of a rectangle with lengths a and b and area ab.
Claude Irwin Palmer Library of Practical Electricity: Practical Mathematics For Home Study (New York: McGraw-Hill Book Company, Inc., 1919) 272
2400×1141, 138.8 KiB
1024×486, 22.1 KiB
640×304, 14.0 KiB
320×152, 5.9 KiB