Finding the Fourth Proportional to 1,078.76, 1,618.38 and 429.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.76 : 1,618.38 = 429.56 : x
2. Step 2: Convert to fraction form
   1,078.76/1,618.38 = 429.56/x
3. Step 3: Cross multiply
   1,078.76x = 1,618.38 × 429.56
4. Step 4: Simplify right side
   1,078.76x = 695,191.31
5. Step 5: Solve for x
   x = 695,191.31/1,078.76
6. Step 6: Final answer
   x = 644.44