Finding the Third Proportional to 641.06 and 919.78

Step by Step Solution

1. Step 1: Write the proportion equation
   641.06 : 919.78 = 919.78 : x
2. Step 2: Convert to fraction form
   641.06/919.78 = 919.78/x
3. Step 3: Cross multiply
   641.06x = 919.78 × 919.78
4. Step 4: Simplify right side
   641.06x = 845,997.55
5. Step 5: Solve for x
   x = 845,997.55/641.06
6. Step 6: Final answer
   x = 1,319.68