Finding the Fourth Proportional to 7,128.57, 9,837.72 and 3,984.75

Step by Step Solution

1. Step 1: Write the proportion equation
   7,128.57 : 9,837.72 = 3,984.75 : x
2. Step 2: Convert to fraction form
   7,128.57/9,837.72 = 3,984.75/x
3. Step 3: Cross multiply
   7,128.57x = 9,837.72 × 3,984.75
4. Step 4: Simplify right side
   7,128.57x = 39,200,854.77
5. Step 5: Solve for x
   x = 39,200,854.77/7,128.57
6. Step 6: Final answer
   x = 5,499.12