Finding the Fourth Proportional to 1,078.72, 1,488.54 and 630.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.72 : 1,488.54 = 630.69 : x
2. Step 2: Convert to fraction form
   1,078.72/1,488.54 = 630.69/x
3. Step 3: Cross multiply
   1,078.72x = 1,488.54 × 630.69
4. Step 4: Simplify right side
   1,078.72x = 938,807.29
5. Step 5: Solve for x
   x = 938,807.29/1,078.72
6. Step 6: Final answer
   x = 870.30