Finding the Fourth Proportional to 13,085.18, 18,057.43 and 7,116.80

Step by Step Solution

1. Step 1: Write the proportion equation
   13,085.18 : 18,057.43 = 7,116.80 : x
2. Step 2: Convert to fraction form
   13,085.18/18,057.43 = 7,116.80/x
3. Step 3: Cross multiply
   13,085.18x = 18,057.43 × 7,116.80
4. Step 4: Simplify right side
   13,085.18x = 128,511,036.43
5. Step 5: Solve for x
   x = 128,511,036.43/13,085.18
6. Step 6: Final answer
   x = 9,821.11