Finding the Fourth Proportional to 2,152.31, 3,228.47 and 613.31

Step by Step Solution

1. Step 1: Write the proportion equation
   2,152.31 : 3,228.47 = 613.31 : x
2. Step 2: Convert to fraction form
   2,152.31/3,228.47 = 613.31/x
3. Step 3: Cross multiply
   2,152.31x = 3,228.47 × 613.31
4. Step 4: Simplify right side
   2,152.31x = 1,980,062.54
5. Step 5: Solve for x
   x = 1,980,062.54/2,152.31
6. Step 6: Final answer
   x = 919.97