Finding the Fourth Proportional to 57,021, 78,688.76 and 31,870.50

Step by Step Solution

1. Step 1: Write the proportion equation
   57,021 : 78,688.76 = 31,870.50 : x
2. Step 2: Convert to fraction form
   57,021/78,688.76 = 31,870.50/x
3. Step 3: Cross multiply
   57,021x = 78,688.76 × 31,870.50
4. Step 4: Simplify right side
   57,021x = 2,507,850,125.58
5. Step 5: Solve for x
   x = 2,507,850,125.58/57,021
6. Step 6: Final answer
   x = 43,981.17