Finding the Fourth Proportional to 1,145.91, 1,581.35 and 621.94

Step by Step Solution

1. Step 1: Write the proportion equation
   1,145.91 : 1,581.35 = 621.94 : x
2. Step 2: Convert to fraction form
   1,145.91/1,581.35 = 621.94/x
3. Step 3: Cross multiply
   1,145.91x = 1,581.35 × 621.94
4. Step 4: Simplify right side
   1,145.91x = 983,502.42
5. Step 5: Solve for x
   x = 983,502.42/1,145.91
6. Step 6: Final answer
   x = 858.27