Finding the Fourth Proportional to 1,111.35, 1,667.31 and 380.94

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.35 : 1,667.31 = 380.94 : x
2. Step 2: Convert to fraction form
   1,111.35/1,667.31 = 380.94/x
3. Step 3: Cross multiply
   1,111.35x = 1,667.31 × 380.94
4. Step 4: Simplify right side
   1,111.35x = 635,136.73
5. Step 5: Solve for x
   x = 635,136.73/1,111.35
6. Step 6: Final answer
   x = 571.50