Finding the Fourth Proportional to 2,606.78, 3,905.30 and 1,309.16

Step by Step Solution

1. Step 1: Write the proportion equation
   2,606.78 : 3,905.30 = 1,309.16 : x
2. Step 2: Convert to fraction form
   2,606.78/3,905.30 = 1,309.16/x
3. Step 3: Cross multiply
   2,606.78x = 3,905.30 × 1,309.16
4. Step 4: Simplify right side
   2,606.78x = 5,112,662.55
5. Step 5: Solve for x
   x = 5,112,662.55/2,606.78
6. Step 6: Final answer
   x = 1,961.29