Finding the Third Proportional to 64 and 71.50

Step by Step Solution

1. Step 1: Write the proportion equation
   64 : 71.50 = 71.50 : x
2. Step 2: Convert to fraction form
   64/71.50 = 71.50/x
3. Step 3: Cross multiply
   64x = 71.50 × 71.50
4. Step 4: Simplify right side
   64x = 5,112.25
5. Step 5: Solve for x
   x = 5,112.25/64
6. Step 6: Final answer
   x = 79.88