Finding the Fourth Proportional to 1,191.12, 1,642.15 and 817.95

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.12 : 1,642.15 = 817.95 : x
2. Step 2: Convert to fraction form
   1,191.12/1,642.15 = 817.95/x
3. Step 3: Cross multiply
   1,191.12x = 1,642.15 × 817.95
4. Step 4: Simplify right side
   1,191.12x = 1,343,196.59
5. Step 5: Solve for x
   x = 1,343,196.59/1,191.12
6. Step 6: Final answer
   x = 1,127.68