Finding the Fourth Proportional to 38,856.72, 58,270.76 and 13,890

Step by Step Solution

1. Step 1: Write the proportion equation
   38,856.72 : 58,270.76 = 13,890 : x
2. Step 2: Convert to fraction form
   38,856.72/58,270.76 = 13,890/x
3. Step 3: Cross multiply
   38,856.72x = 58,270.76 × 13,890
4. Step 4: Simplify right side
   38,856.72x = 809,380,856.40
5. Step 5: Solve for x
   x = 809,380,856.40/38,856.72
6. Step 6: Final answer
   x = 20,829.88