Finding the Third Proportional to 639.94 and 971.72

Step by Step Solution

1. Step 1: Write the proportion equation
   639.94 : 971.72 = 971.72 : x
2. Step 2: Convert to fraction form
   639.94/971.72 = 971.72/x
3. Step 3: Cross multiply
   639.94x = 971.72 × 971.72
4. Step 4: Simplify right side
   639.94x = 944,237.33
5. Step 5: Solve for x
   x = 944,237.33/639.94
6. Step 6: Final answer
   x = 1,475.51