Finding the Fourth Proportional to 1,116.05, 1,540.22 and 643.97

Step by Step Solution

1. Step 1: Write the proportion equation
   1,116.05 : 1,540.22 = 643.97 : x
2. Step 2: Convert to fraction form
   1,116.05/1,540.22 = 643.97/x
3. Step 3: Cross multiply
   1,116.05x = 1,540.22 × 643.97
4. Step 4: Simplify right side
   1,116.05x = 991,856.10
5. Step 5: Solve for x
   x = 991,856.10/1,116.05
6. Step 6: Final answer
   x = 888.72