Finding the Fourth Proportional to 100,819.72, 139,129.86 and 56,107.72

Step by Step Solution

1. Step 1: Write the proportion equation
   100,819.72 : 139,129.86 = 56,107.72 : x
2. Step 2: Convert to fraction form
   100,819.72/139,129.86 = 56,107.72/x
3. Step 3: Cross multiply
   100,819.72x = 139,129.86 × 56,107.72
4. Step 4: Simplify right side
   100,819.72x = 7,806,259,228.52
5. Step 5: Solve for x
   x = 7,806,259,228.52/100,819.72
6. Step 6: Final answer
   x = 77,427.90