Finding the Fourth Proportional to 21,225.38, 29,291.81 and 12,728.88

Step by Step Solution

1. Step 1: Write the proportion equation
   21,225.38 : 29,291.81 = 12,728.88 : x
2. Step 2: Convert to fraction form
   21,225.38/29,291.81 = 12,728.88/x
3. Step 3: Cross multiply
   21,225.38x = 29,291.81 × 12,728.88
4. Step 4: Simplify right side
   21,225.38x = 372,851,870.83
5. Step 5: Solve for x
   x = 372,851,870.83/21,225.38
6. Step 6: Final answer
   x = 17,566.33