Finding the Fourth Proportional to 1,070.80, 1,478.04 and 628.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,070.80 : 1,478.04 = 628.72 : x
2. Step 2: Convert to fraction form
   1,070.80/1,478.04 = 628.72/x
3. Step 3: Cross multiply
   1,070.80x = 1,478.04 × 628.72
4. Step 4: Simplify right side
   1,070.80x = 929,273.31
5. Step 5: Solve for x
   x = 929,273.31/1,070.80
6. Step 6: Final answer
   x = 867.83