Finding the Fourth Proportional to 21,865.50, 30,169.53 and 12,913.38

Step by Step Solution

1. Step 1: Write the proportion equation
   21,865.50 : 30,169.53 = 12,913.38 : x
2. Step 2: Convert to fraction form
   21,865.50/30,169.53 = 12,913.38/x
3. Step 3: Cross multiply
   21,865.50x = 30,169.53 × 12,913.38
4. Step 4: Simplify right side
   21,865.50x = 389,590,605.31
5. Step 5: Solve for x
   x = 389,590,605.31/21,865.50
6. Step 6: Final answer
   x = 17,817.59