Finding the Fourth Proportional to 1,166.72, 1,610.09 and 642.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,166.72 : 1,610.09 = 642.76 : x
2. Step 2: Convert to fraction form
   1,166.72/1,610.09 = 642.76/x
3. Step 3: Cross multiply
   1,166.72x = 1,610.09 × 642.76
4. Step 4: Simplify right side
   1,166.72x = 1,034,902.26
5. Step 5: Solve for x
   x = 1,034,902.26/1,166.72
6. Step 6: Final answer
   x = 887.02