Finding the Fourth Proportional to 1,290.56, 1,936.18 and 828.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.56 : 1,936.18 = 828.55 : x
2. Step 2: Convert to fraction form
   1,290.56/1,936.18 = 828.55/x
3. Step 3: Cross multiply
   1,290.56x = 1,936.18 × 828.55
4. Step 4: Simplify right side
   1,290.56x = 1,604,228.51
5. Step 5: Solve for x
   x = 1,604,228.51/1,290.56
6. Step 6: Final answer
   x = 1,243.05