Finding the Fourth Proportional to 1,111.31, 1,664.90 and 417.54

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.31 : 1,664.90 = 417.54 : x
2. Step 2: Convert to fraction form
   1,111.31/1,664.90 = 417.54/x
3. Step 3: Cross multiply
   1,111.31x = 1,664.90 × 417.54
4. Step 4: Simplify right side
   1,111.31x = 695,162.35
5. Step 5: Solve for x
   x = 695,162.35/1,111.31
6. Step 6: Final answer
   x = 625.53