Finding the Fourth Proportional to 101,128.50, 139,557.39 and 56,416.50

Step by Step Solution

1. Step 1: Write the proportion equation
   101,128.50 : 139,557.39 = 56,416.50 : x
2. Step 2: Convert to fraction form
   101,128.50/139,557.39 = 56,416.50/x
3. Step 3: Cross multiply
   101,128.50x = 139,557.39 × 56,416.50
4. Step 4: Simplify right side
   101,128.50x = 7,873,339,492.94
5. Step 5: Solve for x
   x = 7,873,339,492.94/101,128.50
6. Step 6: Final answer
   x = 77,854.80