Finding the Third Proportional to 411.94 and 641.53

Step by Step Solution

1. Step 1: Write the proportion equation
   411.94 : 641.53 = 641.53 : x
2. Step 2: Convert to fraction form
   411.94/641.53 = 641.53/x
3. Step 3: Cross multiply
   411.94x = 641.53 × 641.53
4. Step 4: Simplify right side
   411.94x = 411,562.34
5. Step 5: Solve for x
   x = 411,562.34/411.94
6. Step 6: Final answer
   x = 999.09