Finding the Fourth Proportional to 1,111.06, 1,667.42 and 418.41

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.06 : 1,667.42 = 418.41 : x
2. Step 2: Convert to fraction form
   1,111.06/1,667.42 = 418.41/x
3. Step 3: Cross multiply
   1,111.06x = 1,667.42 × 418.41
4. Step 4: Simplify right side
   1,111.06x = 697,654.77
5. Step 5: Solve for x
   x = 697,654.77/1,111.06
6. Step 6: Final answer
   x = 627.92