Finding the Fourth Proportional to 21,116.48, 31,683.90 and 13,237.05

Step by Step Solution

1. Step 1: Write the proportion equation
   21,116.48 : 31,683.90 = 13,237.05 : x
2. Step 2: Convert to fraction form
   21,116.48/31,683.90 = 13,237.05/x
3. Step 3: Cross multiply
   21,116.48x = 31,683.90 × 13,237.05
4. Step 4: Simplify right side
   21,116.48x = 419,401,368.50
5. Step 5: Solve for x
   x = 419,401,368.50/21,116.48
6. Step 6: Final answer
   x = 19,861.33