Finding the Fourth Proportional to 21,715.47, 29,970.81 and 12,765.15

Step by Step Solution

1. Step 1: Write the proportion equation
   21,715.47 : 29,970.81 = 12,765.15 : x
2. Step 2: Convert to fraction form
   21,715.47/29,970.81 = 12,765.15/x
3. Step 3: Cross multiply
   21,715.47x = 29,970.81 × 12,765.15
4. Step 4: Simplify right side
   21,715.47x = 382,581,885.27
5. Step 5: Solve for x
   x = 382,581,885.27/21,715.47
6. Step 6: Final answer
   x = 17,617.94