First, we {{CMD_266}}introduce two variables{{CMD_267}}, {{MATH_268}}, the distance from the person to the lamp, and {{MATH_269}}, the length of the shadow. The given rate is {{MATH_270}} ft/s and the unknown (related) rate is {{MATH_271}} at the moment when {{MATH_272}} feet. Next, we {{CMD_273}}draw a picture{{CMD_274}}. {{CMD_275}} {{ENV_276}} {{CMD_277}}