Finding the Fourth Proportional to 2,613.05, 3,919.59 and 665.25

Step by Step Solution

1. Step 1: Write the proportion equation
   2,613.05 : 3,919.59 = 665.25 : x
2. Step 2: Convert to fraction form
   2,613.05/3,919.59 = 665.25/x
3. Step 3: Cross multiply
   2,613.05x = 3,919.59 × 665.25
4. Step 4: Simplify right side
   2,613.05x = 2,607,507.25
5. Step 5: Solve for x
   x = 2,607,507.25/2,613.05
6. Step 6: Final answer
   x = 997.88