A bike to do tricks with has 20-inch-diameter wheels. Find the area of each wheel. Round to the nearest whole number. (Hint: Use the π key on your calculator and round at the last step. If you do not have such a key, use 22/7 for π and round at the last step.) 
 a)314 in.2
 b)1,256 in.2
 c)1,257 in.2
 d)312 in.2