Finding the Fourth Proportional to 21,665.91, 29,899.15 and 12,713.56

Step by Step Solution

1. Step 1: Write the proportion equation
   21,665.91 : 29,899.15 = 12,713.56 : x
2. Step 2: Convert to fraction form
   21,665.91/29,899.15 = 12,713.56/x
3. Step 3: Cross multiply
   21,665.91x = 29,899.15 × 12,713.56
4. Step 4: Simplify right side
   21,665.91x = 380,124,499.16
5. Step 5: Solve for x
   x = 380,124,499.16/21,665.91
6. Step 6: Final answer
   x = 17,544.82