Finding the Fourth Proportional to 13,210.56, 19,809.70 and 7,665.50

Step by Step Solution

1. Step 1: Write the proportion equation
   13,210.56 : 19,809.70 = 7,665.50 : x
2. Step 2: Convert to fraction form
   13,210.56/19,809.70 = 7,665.50/x
3. Step 3: Cross multiply
   13,210.56x = 19,809.70 × 7,665.50
4. Step 4: Simplify right side
   13,210.56x = 151,851,285.71
5. Step 5: Solve for x
   x = 151,851,285.71/13,210.56
6. Step 6: Final answer
   x = 11,494.69