Finding the Fourth Proportional to 5,781.35, 7,978.29 and 3,128.76

Step by Step Solution

1. Step 1: Write the proportion equation
   5,781.35 : 7,978.29 = 3,128.76 : x
2. Step 2: Convert to fraction form
   5,781.35/7,978.29 = 3,128.76/x
3. Step 3: Cross multiply
   5,781.35x = 7,978.29 × 3,128.76
4. Step 4: Simplify right side
   5,781.35x = 24,962,175.45
5. Step 5: Solve for x
   x = 24,962,175.45/5,781.35
6. Step 6: Final answer
   x = 4,317.70