Finding the Fourth Proportional to 1,139.62, 1,572.74 and 697.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.62 : 1,572.74 = 697.50 : x
2. Step 2: Convert to fraction form
   1,139.62/1,572.74 = 697.50/x
3. Step 3: Cross multiply
   1,139.62x = 1,572.74 × 697.50
4. Step 4: Simplify right side
   1,139.62x = 1,096,986.15
5. Step 5: Solve for x
   x = 1,096,986.15/1,139.62
6. Step 6: Final answer
   x = 962.59