Finding the Fourth Proportional to 1,490.45, 2,057.50 and 931.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,490.45 : 2,057.50 = 931.28 : x
2. Step 2: Convert to fraction form
   1,490.45/2,057.50 = 931.28/x
3. Step 3: Cross multiply
   1,490.45x = 2,057.50 × 931.28
4. Step 4: Simplify right side
   1,490.45x = 1,916,111.05
5. Step 5: Solve for x
   x = 1,916,111.05/1,490.45
6. Step 6: Final answer
   x = 1,285.59