Finding the Fourth Proportional to 2,579.78, 3,870.42 and 936.30

Step by Step Solution

1. Step 1: Write the proportion equation
   2,579.78 : 3,870.42 = 936.30 : x
2. Step 2: Convert to fraction form
   2,579.78/3,870.42 = 936.30/x
3. Step 3: Cross multiply
   2,579.78x = 3,870.42 × 936.30
4. Step 4: Simplify right side
   2,579.78x = 3,623,874.25
5. Step 5: Solve for x
   x = 3,623,874.25/2,579.78
6. Step 6: Final answer
   x = 1,404.72