Finding the Fourth Proportional to 1,221.57, 1,685.73 and 697.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,221.57 : 1,685.73 = 697.56 : x
2. Step 2: Convert to fraction form
   1,221.57/1,685.73 = 697.56/x
3. Step 3: Cross multiply
   1,221.57x = 1,685.73 × 697.56
4. Step 4: Simplify right side
   1,221.57x = 1,175,897.82
5. Step 5: Solve for x
   x = 1,175,897.82/1,221.57
6. Step 6: Final answer
   x = 962.61