Finding the Fourth Proportional to 1,145.37, 1,580.61 and 621.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,145.37 : 1,580.61 = 621.39 : x
2. Step 2: Convert to fraction form
   1,145.37/1,580.61 = 621.39/x
3. Step 3: Cross multiply
   1,145.37x = 1,580.61 × 621.39
4. Step 4: Simplify right side
   1,145.37x = 982,175.25
5. Step 5: Solve for x
   x = 982,175.25/1,145.37
6. Step 6: Final answer
   x = 857.52