Finding the Third Proportional to 72.50 and 77.50

Step by Step Solution

1. Step 1: Write the proportion equation
   72.50 : 77.50 = 77.50 : x
2. Step 2: Convert to fraction form
   72.50/77.50 = 77.50/x
3. Step 3: Cross multiply
   72.50x = 77.50 × 77.50
4. Step 4: Simplify right side
   72.50x = 6,006.25
5. Step 5: Solve for x
   x = 6,006.25/72.50
6. Step 6: Final answer
   x = 82.84