Finding the Fourth Proportional to 1,105.21, 1,524.61 and 685.43

Step by Step Solution

1. Step 1: Write the proportion equation
   1,105.21 : 1,524.61 = 685.43 : x
2. Step 2: Convert to fraction form
   1,105.21/1,524.61 = 685.43/x
3. Step 3: Cross multiply
   1,105.21x = 1,524.61 × 685.43
4. Step 4: Simplify right side
   1,105.21x = 1,045,013.43
5. Step 5: Solve for x
   x = 1,045,013.43/1,105.21
6. Step 6: Final answer
   x = 945.53