Finding the Fourth Proportional to 1,141.11, 1,574.69 and 643.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,141.11 : 1,574.69 = 643.69 : x
2. Step 2: Convert to fraction form
   1,141.11/1,574.69 = 643.69/x
3. Step 3: Cross multiply
   1,141.11x = 1,574.69 × 643.69
4. Step 4: Simplify right side
   1,141.11x = 1,013,604.33
5. Step 5: Solve for x
   x = 1,013,604.33/1,141.11
6. Step 6: Final answer
   x = 888.26