Finding the Fourth Proportional to 1,116.78, 1,540.78 and 696.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,116.78 : 1,540.78 = 696.80 : x
2. Step 2: Convert to fraction form
   1,116.78/1,540.78 = 696.80/x
3. Step 3: Cross multiply
   1,116.78x = 1,540.78 × 696.80
4. Step 4: Simplify right side
   1,116.78x = 1,073,615.50
5. Step 5: Solve for x
   x = 1,073,615.50/1,116.78
6. Step 6: Final answer
   x = 961.35