Finding the Fourth Proportional to 2,612.59, 3,918.89 and 664.79

Step by Step Solution

1. Step 1: Write the proportion equation
   2,612.59 : 3,918.89 = 664.79 : x
2. Step 2: Convert to fraction form
   2,612.59/3,918.89 = 664.79/x
3. Step 3: Cross multiply
   2,612.59x = 3,918.89 × 664.79
4. Step 4: Simplify right side
   2,612.59x = 2,605,241.12
5. Step 5: Solve for x
   x = 2,605,241.12/2,612.59
6. Step 6: Final answer
   x = 997.19