Finding the Third Proportional to 641.67 and 1,313.72

Step by Step Solution

1. Step 1: Write the proportion equation
   641.67 : 1,313.72 = 1,313.72 : x
2. Step 2: Convert to fraction form
   641.67/1,313.72 = 1,313.72/x
3. Step 3: Cross multiply
   641.67x = 1,313.72 × 1,313.72
4. Step 4: Simplify right side
   641.67x = 1,725,856.95
5. Step 5: Solve for x
   x = 1,725,856.95/641.67
6. Step 6: Final answer
   x = 2,689.63