Finding the Fourth Proportional to 21,111.82, 29,129.75 and 13,458.01

Step by Step Solution

1. Step 1: Write the proportion equation
   21,111.82 : 29,129.75 = 13,458.01 : x
2. Step 2: Convert to fraction form
   21,111.82/29,129.75 = 13,458.01/x
3. Step 3: Cross multiply
   21,111.82x = 29,129.75 × 13,458.01
4. Step 4: Simplify right side
   21,111.82x = 392,028,387.69
5. Step 5: Solve for x
   x = 392,028,387.69/21,111.82
6. Step 6: Final answer
   x = 18,569.14