Finding the Fourth Proportional to 20,968.35, 31,457.15 and 9,123.99

Step by Step Solution

1. Step 1: Write the proportion equation
   20,968.35 : 31,457.15 = 9,123.99 : x
2. Step 2: Convert to fraction form
   20,968.35/31,457.15 = 9,123.99/x
3. Step 3: Cross multiply
   20,968.35x = 31,457.15 × 9,123.99
4. Step 4: Simplify right side
   20,968.35x = 287,014,676.41
5. Step 5: Solve for x
   x = 287,014,676.41/20,968.35
6. Step 6: Final answer
   x = 13,688.00