Finding the Fourth Proportional to 1,221.49, 1,685.82 and 724.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,221.49 : 1,685.82 = 724.42 : x
2. Step 2: Convert to fraction form
   1,221.49/1,685.82 = 724.42/x
3. Step 3: Cross multiply
   1,221.49x = 1,685.82 × 724.42
4. Step 4: Simplify right side
   1,221.49x = 1,221,241.72
5. Step 5: Solve for x
   x = 1,221,241.72/1,221.49
6. Step 6: Final answer
   x = 999.80