Finding the Fourth Proportional to 1,086.28, 1,499.11 and 620.53

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.28 : 1,499.11 = 620.53 : x
2. Step 2: Convert to fraction form
   1,086.28/1,499.11 = 620.53/x
3. Step 3: Cross multiply
   1,086.28x = 1,499.11 × 620.53
4. Step 4: Simplify right side
   1,086.28x = 930,237.43
5. Step 5: Solve for x
   x = 930,237.43/1,086.28
6. Step 6: Final answer
   x = 856.35