Finding the Fourth Proportional to 1,607.86, 2,409.72 and 827.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,607.86 : 2,409.72 = 827.20 : x
2. Step 2: Convert to fraction form
   1,607.86/2,409.72 = 827.20/x
3. Step 3: Cross multiply
   1,607.86x = 2,409.72 × 827.20
4. Step 4: Simplify right side
   1,607.86x = 1,993,320.38
5. Step 5: Solve for x
   x = 1,993,320.38/1,607.86
6. Step 6: Final answer
   x = 1,239.74