Finding the Fourth Proportional to 21,287.32, 29,350.47 and 13,315.72

Step by Step Solution

1. Step 1: Write the proportion equation
   21,287.32 : 29,350.47 = 13,315.72 : x
2. Step 2: Convert to fraction form
   21,287.32/29,350.47 = 13,315.72/x
3. Step 3: Cross multiply
   21,287.32x = 29,350.47 × 13,315.72
4. Step 4: Simplify right side
   21,287.32x = 390,822,640.39
5. Step 5: Solve for x
   x = 390,822,640.39/21,287.32
6. Step 6: Final answer
   x = 18,359.41