Finding the Fourth Proportional to 1,225.83, 1,691.67 and 666.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,225.83 : 1,691.67 = 666.31 : x
2. Step 2: Convert to fraction form
   1,225.83/1,691.67 = 666.31/x
3. Step 3: Cross multiply
   1,225.83x = 1,691.67 × 666.31
4. Step 4: Simplify right side
   1,225.83x = 1,127,174.33
5. Step 5: Solve for x
   x = 1,127,174.33/1,225.83
6. Step 6: Final answer
   x = 919.52