Finding the Fourth Proportional to 1,080.52, 1,490.72 and 638.08

Step by Step Solution

1. Step 1: Write the proportion equation
   1,080.52 : 1,490.72 = 638.08 : x
2. Step 2: Convert to fraction form
   1,080.52/1,490.72 = 638.08/x
3. Step 3: Cross multiply
   1,080.52x = 1,490.72 × 638.08
4. Step 4: Simplify right side
   1,080.52x = 951,198.62
5. Step 5: Solve for x
   x = 951,198.62/1,080.52
6. Step 6: Final answer
   x = 880.32