Finding the Fourth Proportional to 1,101.78, 1,521.47 and 709.49

Step by Step Solution

1. Step 1: Write the proportion equation
   1,101.78 : 1,521.47 = 709.49 : x
2. Step 2: Convert to fraction form
   1,101.78/1,521.47 = 709.49/x
3. Step 3: Cross multiply
   1,101.78x = 1,521.47 × 709.49
4. Step 4: Simplify right side
   1,101.78x = 1,079,456.60
5. Step 5: Solve for x
   x = 1,079,456.60/1,101.78
6. Step 6: Final answer
   x = 979.74