Finding the Fourth Proportional to 1,061.28, 1,590.24 and 818.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,061.28 : 1,590.24 = 818.40 : x
2. Step 2: Convert to fraction form
   1,061.28/1,590.24 = 818.40/x
3. Step 3: Cross multiply
   1,061.28x = 1,590.24 × 818.40
4. Step 4: Simplify right side
   1,061.28x = 1,301,452.42
5. Step 5: Solve for x
   x = 1,301,452.42/1,061.28
6. Step 6: Final answer
   x = 1,226.30