Finding the Fourth Proportional to 21,428.34, 29,585.72 and 13,365.13

Step by Step Solution

1. Step 1: Write the proportion equation
   21,428.34 : 29,585.72 = 13,365.13 : x
2. Step 2: Convert to fraction form
   21,428.34/29,585.72 = 13,365.13/x
3. Step 3: Cross multiply
   21,428.34x = 29,585.72 × 13,365.13
4. Step 4: Simplify right side
   21,428.34x = 395,416,993.94
5. Step 5: Solve for x
   x = 395,416,993.94/21,428.34
6. Step 6: Final answer
   x = 18,452.99