Finding the Fourth Proportional to 2,459.79, 3,688.59 and 815.49

Step by Step Solution

1. Step 1: Write the proportion equation
   2,459.79 : 3,688.59 = 815.49 : x
2. Step 2: Convert to fraction form
   2,459.79/3,688.59 = 815.49/x
3. Step 3: Cross multiply
   2,459.79x = 3,688.59 × 815.49
4. Step 4: Simplify right side
   2,459.79x = 3,008,008.26
5. Step 5: Solve for x
   x = 3,008,008.26/2,459.79
6. Step 6: Final answer
   x = 1,222.87