Finding the Fourth Proportional to 1,221.72, 1,684.71 and 849.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,221.72 : 1,684.71 = 849.12 : x
2. Step 2: Convert to fraction form
   1,221.72/1,684.71 = 849.12/x
3. Step 3: Cross multiply
   1,221.72x = 1,684.71 × 849.12
4. Step 4: Simplify right side
   1,221.72x = 1,430,520.96
5. Step 5: Solve for x
   x = 1,430,520.96/1,221.72
6. Step 6: Final answer
   x = 1,170.91