Finding the Fourth Proportional to 1,079.98, 1,490.56 and 638.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,079.98 : 1,490.56 = 638.12 : x
2. Step 2: Convert to fraction form
   1,079.98/1,490.56 = 638.12/x
3. Step 3: Cross multiply
   1,079.98x = 1,490.56 × 638.12
4. Step 4: Simplify right side
   1,079.98x = 951,156.15
5. Step 5: Solve for x
   x = 951,156.15/1,079.98
6. Step 6: Final answer
   x = 880.72