Finding the Fourth Proportional to 1,108.69, 1,529.89 and 611.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,108.69 : 1,529.89 = 611.21 : x
2. Step 2: Convert to fraction form
   1,108.69/1,529.89 = 611.21/x
3. Step 3: Cross multiply
   1,108.69x = 1,529.89 × 611.21
4. Step 4: Simplify right side
   1,108.69x = 935,074.89
5. Step 5: Solve for x
   x = 935,074.89/1,108.69
6. Step 6: Final answer
   x = 843.40