Finding the Fourth Proportional to 1,131.72, 1,562.28 and 666

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.72 : 1,562.28 = 666 : x
2. Step 2: Convert to fraction form
   1,131.72/1,562.28 = 666/x
3. Step 3: Cross multiply
   1,131.72x = 1,562.28 × 666
4. Step 4: Simplify right side
   1,131.72x = 1,040,478.48
5. Step 5: Solve for x
   x = 1,040,478.48/1,131.72
6. Step 6: Final answer
   x = 919.38