Area of Sphere Small 320×102 Medium 640×205 Large 1024×328 Download Tiff Original 2400×768 | (192.3 KB) Description "It is found that the cord covering the curved surface is twice as long as the one covering the flat surface. So the area of the entire curved surface of a sphere is equal to the area of the surface of 4 circles like the one measured." -Foster, 1921 Keywords cord method, find area, geometry, math, sphere area, sphere in halves, Spherical Galleries Spheres Source: Ellsworth D. Foster ed. The American Educator (vol. 1) (Chicago, IL: Ralph Durham Company, 1921) Courtesy the private collection of Roy Winkelman
