Finding the Fourth Proportional to 2,459.56, 3,688.58 and 815.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,459.56 : 3,688.58 = 815.78 : x
2. Step 2: Convert to fraction form
   2,459.56/3,688.58 = 815.78/x
3. Step 3: Cross multiply
   2,459.56x = 3,688.58 × 815.78
4. Step 4: Simplify right side
   2,459.56x = 3,009,069.79
5. Step 5: Solve for x
   x = 3,009,069.79/2,459.56
6. Step 6: Final answer
   x = 1,223.42