Finding the Fourth Proportional to 1,139.60, 1,572.30 and 697.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.60 : 1,572.30 = 697.05 : x
2. Step 2: Convert to fraction form
   1,139.60/1,572.30 = 697.05/x
3. Step 3: Cross multiply
   1,139.60x = 1,572.30 × 697.05
4. Step 4: Simplify right side
   1,139.60x = 1,095,971.72
5. Step 5: Solve for x
   x = 1,095,971.72/1,139.60
6. Step 6: Final answer
   x = 961.71