Finding the Fourth Proportional to 1,078.48, 1,488.48 and 636.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.48 : 1,488.48 = 636.72 : x
2. Step 2: Convert to fraction form
   1,078.48/1,488.48 = 636.72/x
3. Step 3: Cross multiply
   1,078.48x = 1,488.48 × 636.72
4. Step 4: Simplify right side
   1,078.48x = 947,744.99
5. Step 5: Solve for x
   x = 947,744.99/1,078.48
6. Step 6: Final answer
   x = 878.78