Finding the Fourth Proportional to 1,317.72, 1,818.62 and 820.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,317.72 : 1,818.62 = 820.18 : x
2. Step 2: Convert to fraction form
   1,317.72/1,818.62 = 820.18/x
3. Step 3: Cross multiply
   1,317.72x = 1,818.62 × 820.18
4. Step 4: Simplify right side
   1,317.72x = 1,491,595.75
5. Step 5: Solve for x
   x = 1,491,595.75/1,317.72
6. Step 6: Final answer
   x = 1,131.95