Finding the Fourth Proportional to 56,640.79, 78,165.56 and 31,145.54

Step by Step Solution

1. Step 1: Write the proportion equation
   56,640.79 : 78,165.56 = 31,145.54 : x
2. Step 2: Convert to fraction form
   56,640.79/78,165.56 = 31,145.54/x
3. Step 3: Cross multiply
   56,640.79x = 78,165.56 × 31,145.54
4. Step 4: Simplify right side
   56,640.79x = 2,434,508,575.60
5. Step 5: Solve for x
   x = 2,434,508,575.60/56,640.79
6. Step 6: Final answer
   x = 42,981.54