Finding the Fourth Proportional to 56,620.50, 78,138.72 and 31,470

Step by Step Solution

1. Step 1: Write the proportion equation
   56,620.50 : 78,138.72 = 31,470 : x
2. Step 2: Convert to fraction form
   56,620.50/78,138.72 = 31,470/x
3. Step 3: Cross multiply
   56,620.50x = 78,138.72 × 31,470
4. Step 4: Simplify right side
   56,620.50x = 2,459,025,518.40
5. Step 5: Solve for x
   x = 2,459,025,518.40/56,620.50
6. Step 6: Final answer
   x = 43,429.95