Finding the Third Proportional to 51,128 and 78,556

Step by Step Solution

1. Step 1: Write the proportion equation
   51,128 : 78,556 = 78,556 : x
2. Step 2: Convert to fraction form
   51,128/78,556 = 78,556/x
3. Step 3: Cross multiply
   51,128x = 78,556 × 78,556
4. Step 4: Simplify right side
   51,128x = 6,171,045,136
5. Step 5: Solve for x
   x = 6,171,045,136/51,128
6. Step 6: Final answer
   x = 120,697.96