Finding the Fourth Proportional to 1,111.43, 1,667.55 and 381.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.43 : 1,667.55 = 381.21 : x
2. Step 2: Convert to fraction form
   1,111.43/1,667.55 = 381.21/x
3. Step 3: Cross multiply
   1,111.43x = 1,667.55 × 381.21
4. Step 4: Simplify right side
   1,111.43x = 635,686.74
5. Step 5: Solve for x
   x = 635,686.74/1,111.43
6. Step 6: Final answer
   x = 571.96