Finding the Fourth Proportional to 1,111.31, 1,666.32 and 380.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.31 : 1,666.32 = 380.69 : x
2. Step 2: Convert to fraction form
   1,111.31/1,666.32 = 380.69/x
3. Step 3: Cross multiply
   1,111.31x = 1,666.32 × 380.69
4. Step 4: Simplify right side
   1,111.31x = 634,351.36
5. Step 5: Solve for x
   x = 634,351.36/1,111.31
6. Step 6: Final answer
   x = 570.81