Finding the Fourth Proportional to 2,215.86, 3,325.46 and 830.55

Step by Step Solution

1. Step 1: Write the proportion equation
   2,215.86 : 3,325.46 = 830.55 : x
2. Step 2: Convert to fraction form
   2,215.86/3,325.46 = 830.55/x
3. Step 3: Cross multiply
   2,215.86x = 3,325.46 × 830.55
4. Step 4: Simplify right side
   2,215.86x = 2,761,969.12
5. Step 5: Solve for x
   x = 2,761,969.12/2,215.86
6. Step 6: Final answer
   x = 1,246.46