Finding the Fourth Proportional to 1,383.12, 1,909.08 and 1,161.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,383.12 : 1,909.08 = 1,161.72 : x
2. Step 2: Convert to fraction form
   1,383.12/1,909.08 = 1,161.72/x
3. Step 3: Cross multiply
   1,383.12x = 1,909.08 × 1,161.72
4. Step 4: Simplify right side
   1,383.12x = 2,217,816.42
5. Step 5: Solve for x
   x = 2,217,816.42/1,383.12
6. Step 6: Final answer
   x = 1,603.49