Finding the Fourth Proportional to 1,221.49, 1,685.69 and 697.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,221.49 : 1,685.69 = 697.57 : x
2. Step 2: Convert to fraction form
   1,221.49/1,685.69 = 697.57/x
3. Step 3: Cross multiply
   1,221.49x = 1,685.69 × 697.57
4. Step 4: Simplify right side
   1,221.49x = 1,175,886.77
5. Step 5: Solve for x
   x = 1,175,886.77/1,221.49
6. Step 6: Final answer
   x = 962.67