Finding the Fourth Proportional to 1,145.83, 1,581.28 and 621.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,145.83 : 1,581.28 = 621.86 : x
2. Step 2: Convert to fraction form
   1,145.83/1,581.28 = 621.86/x
3. Step 3: Cross multiply
   1,145.83x = 1,581.28 × 621.86
4. Step 4: Simplify right side
   1,145.83x = 983,337.18
5. Step 5: Solve for x
   x = 983,337.18/1,145.83
6. Step 6: Final answer
   x = 858.19