Finding the Third Proportional to 640.50 and 1,086.38

Step by Step Solution

1. Step 1: Write the proportion equation
   640.50 : 1,086.38 = 1,086.38 : x
2. Step 2: Convert to fraction form
   640.50/1,086.38 = 1,086.38/x
3. Step 3: Cross multiply
   640.50x = 1,086.38 × 1,086.38
4. Step 4: Simplify right side
   640.50x = 1,180,210.64
5. Step 5: Solve for x
   x = 1,180,210.64/640.50
6. Step 6: Final answer
   x = 1,842.64