Finding the Fourth Proportional to 1,048.40, 1,446.72 and 628.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,048.40 : 1,446.72 = 628.78 : x
2. Step 2: Convert to fraction form
   1,048.40/1,446.72 = 628.78/x
3. Step 3: Cross multiply
   1,048.40x = 1,446.72 × 628.78
4. Step 4: Simplify right side
   1,048.40x = 909,668.60
5. Step 5: Solve for x
   x = 909,668.60/1,048.40
6. Step 6: Final answer
   x = 867.67