Finding the Fourth Proportional to 1,131.16, 1,561.08 and 665.68

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.16 : 1,561.08 = 665.68 : x
2. Step 2: Convert to fraction form
   1,131.16/1,561.08 = 665.68/x
3. Step 3: Cross multiply
   1,131.16x = 1,561.08 × 665.68
4. Step 4: Simplify right side
   1,131.16x = 1,039,179.73
5. Step 5: Solve for x
   x = 1,039,179.73/1,131.16
6. Step 6: Final answer
   x = 918.69