Finding the Fourth Proportional to 1,076.16, 1,613.52 and 426.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,076.16 : 1,613.52 = 426.72 : x
2. Step 2: Convert to fraction form
   1,076.16/1,613.52 = 426.72/x
3. Step 3: Cross multiply
   1,076.16x = 1,613.52 × 426.72
4. Step 4: Simplify right side
   1,076.16x = 688,521.25
5. Step 5: Solve for x
   x = 688,521.25/1,076.16
6. Step 6: Final answer
   x = 639.79