Finding the Fourth Proportional to 1,055.31, 1,456.30 and 613.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,055.31 : 1,456.30 = 613.20 : x
2. Step 2: Convert to fraction form
   1,055.31/1,456.30 = 613.20/x
3. Step 3: Cross multiply
   1,055.31x = 1,456.30 × 613.20
4. Step 4: Simplify right side
   1,055.31x = 893,003.16
5. Step 5: Solve for x
   x = 893,003.16/1,055.31
6. Step 6: Final answer
   x = 846.20