Finding the Third Proportional to 648.50 and 711.50

Step by Step Solution

1. Step 1: Write the proportion equation
   648.50 : 711.50 = 711.50 : x
2. Step 2: Convert to fraction form
   648.50/711.50 = 711.50/x
3. Step 3: Cross multiply
   648.50x = 711.50 × 711.50
4. Step 4: Simplify right side
   648.50x = 506,232.25
5. Step 5: Solve for x
   x = 506,232.25/648.50
6. Step 6: Final answer
   x = 780.62