Finding the Fourth Proportional to 1,111.79, 1,666.56 and 380.87

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.79 : 1,666.56 = 380.87 : x
2. Step 2: Convert to fraction form
   1,111.79/1,666.56 = 380.87/x
3. Step 3: Cross multiply
   1,111.79x = 1,666.56 × 380.87
4. Step 4: Simplify right side
   1,111.79x = 634,734.37
5. Step 5: Solve for x
   x = 634,734.37/1,111.79
6. Step 6: Final answer
   x = 570.91