Finding the Fourth Proportional to 1,191.17, 1,642.55 and 818.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.17 : 1,642.55 = 818.69 : x
2. Step 2: Convert to fraction form
   1,191.17/1,642.55 = 818.69/x
3. Step 3: Cross multiply
   1,191.17x = 1,642.55 × 818.69
4. Step 4: Simplify right side
   1,191.17x = 1,344,726.95
5. Step 5: Solve for x
   x = 1,344,726.95/1,191.17
6. Step 6: Final answer
   x = 1,128.92