Finding the Third Proportional to 51,856 and 81,510

Step by Step Solution

1. Step 1: Write the proportion equation
   51,856 : 81,510 = 81,510 : x
2. Step 2: Convert to fraction form
   51,856/81,510 = 81,510/x
3. Step 3: Cross multiply
   51,856x = 81,510 × 81,510
4. Step 4: Simplify right side
   51,856x = 6,643,880,100
5. Step 5: Solve for x
   x = 6,643,880,100/51,856
6. Step 6: Final answer
   x = 128,121.72