use the geometric sequence formula to solve for rate: an=a1r^(n-1)
6.75=4.5r^(2-1) 6.75=4.5r 6.75/4.5=r r= 1.5 and if you want to make sure just multiply each number by 1.5 and see if it gets you the next number 4.5 4.5×1.5=6.75 (holds true) 6.75 6.75×1.5=10.125 (holds true) 10.125 10.125×1.5=15.1875 (holds true) 15.1875