The forth proportional to 15,30,45 is? Pick
A) 100
B) 45
C) 90
D) 75
E) 100
Let the fourth proportional to 15,30,45 be x   then 15:30::45:x   15x = 30*45   x = 90   Answer is 90
<result>C</result>
The forth proportional to 15,30,45 is?