Finding the Fourth Proportional to 12,806.56, 17,532.20 and 12,720.16

Step by Step Solution

1. Step 1: Write the proportion equation
   12,806.56 : 17,532.20 = 12,720.16 : x
2. Step 2: Convert to fraction form
   12,806.56/17,532.20 = 12,720.16/x
3. Step 3: Cross multiply
   12,806.56x = 17,532.20 × 12,720.16
4. Step 4: Simplify right side
   12,806.56x = 223,012,389.15
5. Step 5: Solve for x
   x = 223,012,389.15/12,806.56
6. Step 6: Final answer
   x = 17,413.92