Rectangle ... a to the power of 4 yards times a to the power of 9 yards

So a rectangle with a^4 times a^9

when multiplying exponents, you just add the exponents because x^4 times x^9 is the same as x*x*x*x times x*x*x*x*x*x*x*x*x and you would get a^13 or a to the power of 13