Finding the Fourth Proportional to 1,218.69, 1,681.78 and 659.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,218.69 : 1,681.78 = 659.15 : x
2. Step 2: Convert to fraction form
   1,218.69/1,681.78 = 659.15/x
3. Step 3: Cross multiply
   1,218.69x = 1,681.78 × 659.15
4. Step 4: Simplify right side
   1,218.69x = 1,108,553.94
5. Step 5: Solve for x
   x = 1,108,553.94/1,218.69
6. Step 6: Final answer
   x = 909.63