Finding the Fourth Proportional to 1,145.69, 1,581.06 and 621.73

Step by Step Solution

1. Step 1: Write the proportion equation
   1,145.69 : 1,581.06 = 621.73 : x
2. Step 2: Convert to fraction form
   1,145.69/1,581.06 = 621.73/x
3. Step 3: Cross multiply
   1,145.69x = 1,581.06 × 621.73
4. Step 4: Simplify right side
   1,145.69x = 982,992.43
5. Step 5: Solve for x
   x = 982,992.43/1,145.69
6. Step 6: Final answer
   x = 857.99