Finding the Fourth Proportional to 1,072.72, 1,478.28 and 722.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,072.72 : 1,478.28 = 722.80 : x
2. Step 2: Convert to fraction form
   1,072.72/1,478.28 = 722.80/x
3. Step 3: Cross multiply
   1,072.72x = 1,478.28 × 722.80
4. Step 4: Simplify right side
   1,072.72x = 1,068,500.78
5. Step 5: Solve for x
   x = 1,068,500.78/1,072.72
6. Step 6: Final answer
   x = 996.07