Finding the Fourth Proportional to 2,061.40, 3,090.60 and 828.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,061.40 : 3,090.60 = 828.20 : x
2. Step 2: Convert to fraction form
   2,061.40/3,090.60 = 828.20/x
3. Step 3: Cross multiply
   2,061.40x = 3,090.60 × 828.20
4. Step 4: Simplify right side
   2,061.40x = 2,559,634.92
5. Step 5: Solve for x
   x = 2,559,634.92/2,061.40
6. Step 6: Final answer
   x = 1,241.70