Finding the Fourth Proportional to 1,076.10, 1,613.69 and 426.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,076.10 : 1,613.69 = 426.38 : x
2. Step 2: Convert to fraction form
   1,076.10/1,613.69 = 426.38/x
3. Step 3: Cross multiply
   1,076.10x = 1,613.69 × 426.38
4. Step 4: Simplify right side
   1,076.10x = 688,036.54
5. Step 5: Solve for x
   x = 688,036.54/1,076.10
6. Step 6: Final answer
   x = 639.38