Finding the Fourth Proportional to 2,485.32, 3,728.31 and 818.90

Step by Step Solution

1. Step 1: Write the proportion equation
   2,485.32 : 3,728.31 = 818.90 : x
2. Step 2: Convert to fraction form
   2,485.32/3,728.31 = 818.90/x
3. Step 3: Cross multiply
   2,485.32x = 3,728.31 × 818.90
4. Step 4: Simplify right side
   2,485.32x = 3,053,094.42
5. Step 5: Solve for x
   x = 3,053,094.42/2,485.32
6. Step 6: Final answer
   x = 1,228.45