Finding the Fourth Proportional to 1,072.20, 1,479.56 and 630.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,072.20 : 1,479.56 = 630.12 : x
2. Step 2: Convert to fraction form
   1,072.20/1,479.56 = 630.12/x
3. Step 3: Cross multiply
   1,072.20x = 1,479.56 × 630.12
4. Step 4: Simplify right side
   1,072.20x = 932,300.35
5. Step 5: Solve for x
   x = 932,300.35/1,072.20
6. Step 6: Final answer
   x = 869.52