Finding the Fourth Proportional to 1,145.46, 1,580.74 and 621.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,145.46 : 1,580.74 = 621.50 : x
2. Step 2: Convert to fraction form
   1,145.46/1,580.74 = 621.50/x
3. Step 3: Cross multiply
   1,145.46x = 1,580.74 × 621.50
4. Step 4: Simplify right side
   1,145.46x = 982,420.45
5. Step 5: Solve for x
   x = 982,420.45/1,145.46
6. Step 6: Final answer
   x = 857.66