Finding the Third Proportional to 12,928 and 20,140

Step by Step Solution

1. Step 1: Write the proportion equation
   12,928 : 20,140 = 20,140 : x
2. Step 2: Convert to fraction form
   12,928/20,140 = 20,140/x
3. Step 3: Cross multiply
   12,928x = 20,140 × 20,140
4. Step 4: Simplify right side
   12,928x = 405,619,600
5. Step 5: Solve for x
   x = 405,619,600/12,928
6. Step 6: Final answer
   x = 31,375.28