Finding the Fourth Proportional to 9,918.06, 13,685.40 and 5,725.50

Step by Step Solution

1. Step 1: Write the proportion equation
   9,918.06 : 13,685.40 = 5,725.50 : x
2. Step 2: Convert to fraction form
   9,918.06/13,685.40 = 5,725.50/x
3. Step 3: Cross multiply
   9,918.06x = 13,685.40 × 5,725.50
4. Step 4: Simplify right side
   9,918.06x = 78,355,757.70
5. Step 5: Solve for x
   x = 78,355,757.70/9,918.06
6. Step 6: Final answer
   x = 7,900.31