Finding the Fourth Proportional to 20,978.28, 31,459.86 and 7,124.04

Step by Step Solution

1. Step 1: Write the proportion equation
   20,978.28 : 31,459.86 = 7,124.04 : x
2. Step 2: Convert to fraction form
   20,978.28/31,459.86 = 7,124.04/x
3. Step 3: Cross multiply
   20,978.28x = 31,459.86 × 7,124.04
4. Step 4: Simplify right side
   20,978.28x = 224,121,301.03
5. Step 5: Solve for x
   x = 224,121,301.03/20,978.28
6. Step 6: Final answer
   x = 10,683.49