Finding the Fourth Proportional to 1,167.31, 1,610.81 and 643.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,167.31 : 1,610.81 = 643.34 : x
2. Step 2: Convert to fraction form
   1,167.31/1,610.81 = 643.34/x
3. Step 3: Cross multiply
   1,167.31x = 1,610.81 × 643.34
4. Step 4: Simplify right side
   1,167.31x = 1,036,295.69
5. Step 5: Solve for x
   x = 1,036,295.69/1,167.31
6. Step 6: Final answer
   x = 887.77