Archie designs an arch to serve as an outdoor sculpture in a park. The arch is to be a certain width and a certain height. To achieve the size and shape for the strongest arch, Archie suspends a chain from the two supports of equal heights that are as far apart as the arch is wide. Archie allows the chain to hang as low as the arch is high. He builds the arch to have exactly the shape of the hanging chain, but inverted. Explain.

Abox that has self-contained cable clamps holds two light switches. a two-wire no. 12 cable with ground feeds the box, and a pair of two-wire no. 12 cables (four conductors) with ground wires leaves the box to feed the light fixtures. the second switch is fed by a no. 12 jumper wire from the first switch. which one of the following box combinations would furnish the minimum allowable volume? a. two 3-inch × 2-inch × 21⁄2-inch gangable device boxes b. two 3-inch × 2-inch × 11⁄2-inch gangable device boxes c. two 3-inch × 2-inch × 23⁄4-inch gangable device boxes d. two 3-inch × 2-inch × 21⁄4-inch gangable device boxes