Finding the Fourth Proportional to 1,111.25, 1,667.10 and 380.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.25 : 1,667.10 = 380.88 : x
2. Step 2: Convert to fraction form
   1,111.25/1,667.10 = 380.88/x
3. Step 3: Cross multiply
   1,111.25x = 1,667.10 × 380.88
4. Step 4: Simplify right side
   1,111.25x = 634,964.33
5. Step 5: Solve for x
   x = 634,964.33/1,111.25
6. Step 6: Final answer
   x = 571.40