Finding the Fourth Proportional to 1,278.26, 1,763.98 and 718.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,278.26 : 1,763.98 = 718.72 : x
2. Step 2: Convert to fraction form
   1,278.26/1,763.98 = 718.72/x
3. Step 3: Cross multiply
   1,278.26x = 1,763.98 × 718.72
4. Step 4: Simplify right side
   1,278.26x = 1,267,801.50
5. Step 5: Solve for x
   x = 1,267,801.50/1,278.26
6. Step 6: Final answer
   x = 991.82