Finding the Fourth Proportional to 21,520.50, 29,698.56 and 13,022.79

Step by Step Solution

1. Step 1: Write the proportion equation
   21,520.50 : 29,698.56 = 13,022.79 : x
2. Step 2: Convert to fraction form
   21,520.50/29,698.56 = 13,022.79/x
3. Step 3: Cross multiply
   21,520.50x = 29,698.56 × 13,022.79
4. Step 4: Simplify right side
   21,520.50x = 386,758,110.18
5. Step 5: Solve for x
   x = 386,758,110.18/21,520.50
6. Step 6: Final answer
   x = 17,971.61