Finding the Fourth Proportional to 1,139.24, 1,572.31 and 691.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.24 : 1,572.31 = 691.34 : x
2. Step 2: Convert to fraction form
   1,139.24/1,572.31 = 691.34/x
3. Step 3: Cross multiply
   1,139.24x = 1,572.31 × 691.34
4. Step 4: Simplify right side
   1,139.24x = 1,086,993.80
5. Step 5: Solve for x
   x = 1,086,993.80/1,139.24
6. Step 6: Final answer
   x = 954.14