Finding the Fourth Proportional to 1,015.76, 1,401.72 and 622.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,015.76 : 1,401.72 = 622.72 : x
2. Step 2: Convert to fraction form
   1,015.76/1,401.72 = 622.72/x
3. Step 3: Cross multiply
   1,015.76x = 1,401.72 × 622.72
4. Step 4: Simplify right side
   1,015.76x = 872,879.08
5. Step 5: Solve for x
   x = 872,879.08/1,015.76
6. Step 6: Final answer
   x = 859.34