Write three functions (1) rectangle Area (2) circleArea, and (3) triangle Area to compute and return the area of a rectangle, circle, and triangle, respectively. Use these functions in a program in which program will compute and print the area of (a) rectangle if user will enter 'R' or 'r'; (b) circle if user will enter 'C' or 'c'; (c) triangle if user will enter 'T' or 't'; The program will discontinue (stop) if user will enter 'E' or 'e'.