Finding the Fourth Proportional to 1,278.42, 1,763.82 and 718.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,278.42 : 1,763.82 = 718.80 : x
2. Step 2: Convert to fraction form
   1,278.42/1,763.82 = 718.80/x
3. Step 3: Cross multiply
   1,278.42x = 1,763.82 × 718.80
4. Step 4: Simplify right side
   1,278.42x = 1,267,833.82
5. Step 5: Solve for x
   x = 1,267,833.82/1,278.42
6. Step 6: Final answer
   x = 991.72