Finding the Fourth Proportional to 1,138.71, 1,571.27 and 666.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,138.71 : 1,571.27 = 666.69 : x
2. Step 2: Convert to fraction form
   1,138.71/1,571.27 = 666.69/x
3. Step 3: Cross multiply
   1,138.71x = 1,571.27 × 666.69
4. Step 4: Simplify right side
   1,138.71x = 1,047,550.00
5. Step 5: Solve for x
   x = 1,047,550.00/1,138.71
6. Step 6: Final answer
   x = 919.94