Finding the Fourth Proportional to 56,128.88, 77,457.96 and 30,978.36

Step by Step Solution

1. Step 1: Write the proportion equation
   56,128.88 : 77,457.96 = 30,978.36 : x
2. Step 2: Convert to fraction form
   56,128.88/77,457.96 = 30,978.36/x
3. Step 3: Cross multiply
   56,128.88x = 77,457.96 × 30,978.36
4. Step 4: Simplify right side
   56,128.88x = 2,399,520,569.75
5. Step 5: Solve for x
   x = 2,399,520,569.75/56,128.88
6. Step 6: Final answer
   x = 42,750.20