Finding the Fourth Proportional to 1,278.27, 1,763.89 and 718.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,278.27 : 1,763.89 = 718.61 : x
2. Step 2: Convert to fraction form
   1,278.27/1,763.89 = 718.61/x
3. Step 3: Cross multiply
   1,278.27x = 1,763.89 × 718.61
4. Step 4: Simplify right side
   1,278.27x = 1,267,548.99
5. Step 5: Solve for x
   x = 1,267,548.99/1,278.27
6. Step 6: Final answer
   x = 991.61