Finding the Fourth Proportional to 1,117.72, 1,676.69 and 387.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,117.72 : 1,676.69 = 387.12 : x
2. Step 2: Convert to fraction form
   1,117.72/1,676.69 = 387.12/x
3. Step 3: Cross multiply
   1,117.72x = 1,676.69 × 387.12
4. Step 4: Simplify right side
   1,117.72x = 649,078.30
5. Step 5: Solve for x
   x = 649,078.30/1,117.72
6. Step 6: Final answer
   x = 580.72