Finding the Fourth Proportional to 1,191.09, 1,643.05 and 718.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.09 : 1,643.05 = 718.71 : x
2. Step 2: Convert to fraction form
   1,191.09/1,643.05 = 718.71/x
3. Step 3: Cross multiply
   1,191.09x = 1,643.05 × 718.71
4. Step 4: Simplify right side
   1,191.09x = 1,180,871.20
5. Step 5: Solve for x
   x = 1,180,871.20/1,191.09
6. Step 6: Final answer
   x = 991.42