Finding the Third Proportional to 519.50 and 810.50

Step by Step Solution

1. Step 1: Write the proportion equation
   519.50 : 810.50 = 810.50 : x
2. Step 2: Convert to fraction form
   519.50/810.50 = 810.50/x
3. Step 3: Cross multiply
   519.50x = 810.50 × 810.50
4. Step 4: Simplify right side
   519.50x = 656,910.25
5. Step 5: Solve for x
   x = 656,910.25/519.50
6. Step 6: Final answer
   x = 1,264.50