Finding the Fourth Proportional to 1,141.34, 1,575.12 and 643.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,141.34 : 1,575.12 = 643.89 : x
2. Step 2: Convert to fraction form
   1,141.34/1,575.12 = 643.89/x
3. Step 3: Cross multiply
   1,141.34x = 1,575.12 × 643.89
4. Step 4: Simplify right side
   1,141.34x = 1,014,204.02
5. Step 5: Solve for x
   x = 1,014,204.02/1,141.34
6. Step 6: Final answer
   x = 888.61