Finding the Fourth Proportional to 1,141.26, 1,574.89 and 643.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,141.26 : 1,574.89 = 643.88 : x
2. Step 2: Convert to fraction form
   1,141.26/1,574.89 = 643.88/x
3. Step 3: Cross multiply
   1,141.26x = 1,574.89 × 643.88
4. Step 4: Simplify right side
   1,141.26x = 1,014,033.91
5. Step 5: Solve for x
   x = 1,014,033.91/1,141.26
6. Step 6: Final answer
   x = 888.53