Finding the Fourth Proportional to 1,940.91, 2,911.82 and 642.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,940.91 : 2,911.82 = 642.38 : x
2. Step 2: Convert to fraction form
   1,940.91/2,911.82 = 642.38/x
3. Step 3: Cross multiply
   1,940.91x = 2,911.82 × 642.38
4. Step 4: Simplify right side
   1,940.91x = 1,870,477.16
5. Step 5: Solve for x
   x = 1,870,477.16/1,940.91
6. Step 6: Final answer
   x = 963.71