Finding the Fourth Proportional to 1,130.78, 1,560.89 and 711.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,130.78 : 1,560.89 = 711.25 : x
2. Step 2: Convert to fraction form
   1,130.78/1,560.89 = 711.25/x
3. Step 3: Cross multiply
   1,130.78x = 1,560.89 × 711.25
4. Step 4: Simplify right side
   1,130.78x = 1,110,180.89
5. Step 5: Solve for x
   x = 1,110,180.89/1,130.78
6. Step 6: Final answer
   x = 981.79