Finding the Fourth Proportional to 1,039.48, 1,434.54 and 666.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,039.48 : 1,434.54 = 666.28 : x
2. Step 2: Convert to fraction form
   1,039.48/1,434.54 = 666.28/x
3. Step 3: Cross multiply
   1,039.48x = 1,434.54 × 666.28
4. Step 4: Simplify right side
   1,039.48x = 955,805.31
5. Step 5: Solve for x
   x = 955,805.31/1,039.48
6. Step 6: Final answer
   x = 919.50