Finding the Fourth Proportional to 5,128.22, 7,685.76 and 2,789.30

Step by Step Solution

1. Step 1: Write the proportion equation
   5,128.22 : 7,685.76 = 2,789.30 : x
2. Step 2: Convert to fraction form
   5,128.22/7,685.76 = 2,789.30/x
3. Step 3: Cross multiply
   5,128.22x = 7,685.76 × 2,789.30
4. Step 4: Simplify right side
   5,128.22x = 21,437,890.37
5. Step 5: Solve for x
   x = 21,437,890.37/5,128.22
6. Step 6: Final answer
   x = 4,180.38