Finding the Fourth Proportional to 2,580.68, 3,870.69 and 825.86

Step by Step Solution

1. Step 1: Write the proportion equation
   2,580.68 : 3,870.69 = 825.86 : x
2. Step 2: Convert to fraction form
   2,580.68/3,870.69 = 825.86/x
3. Step 3: Cross multiply
   2,580.68x = 3,870.69 × 825.86
4. Step 4: Simplify right side
   2,580.68x = 3,196,648.04
5. Step 5: Solve for x
   x = 3,196,648.04/2,580.68
6. Step 6: Final answer
   x = 1,238.69