Finding the Fourth Proportional to 2,300.78, 3,451.21 and 840.08

Step by Step Solution

1. Step 1: Write the proportion equation
   2,300.78 : 3,451.21 = 840.08 : x
2. Step 2: Convert to fraction form
   2,300.78/3,451.21 = 840.08/x
3. Step 3: Cross multiply
   2,300.78x = 3,451.21 × 840.08
4. Step 4: Simplify right side
   2,300.78x = 2,899,299.02
5. Step 5: Solve for x
   x = 2,899,299.02/2,300.78
6. Step 6: Final answer
   x = 1,260.14