Finding the Fourth Proportional to 1,145.79, 1,581.20 and 621.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,145.79 : 1,581.20 = 621.82 : x
2. Step 2: Convert to fraction form
   1,145.79/1,581.20 = 621.82/x
3. Step 3: Cross multiply
   1,145.79x = 1,581.20 × 621.82
4. Step 4: Simplify right side
   1,145.79x = 983,221.78
5. Step 5: Solve for x
   x = 983,221.78/1,145.79
6. Step 6: Final answer
   x = 858.12