Finding the Fourth Proportional to 1,152.78, 1,728.72 and 412.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,152.78 : 1,728.72 = 412.38 : x
2. Step 2: Convert to fraction form
   1,152.78/1,728.72 = 412.38/x
3. Step 3: Cross multiply
   1,152.78x = 1,728.72 × 412.38
4. Step 4: Simplify right side
   1,152.78x = 712,889.55
5. Step 5: Solve for x
   x = 712,889.55/1,152.78
6. Step 6: Final answer
   x = 618.41