Finding the Third Proportional to 7,840 and 12,608

Step by Step Solution

1. Step 1: Write the proportion equation
   7,840 : 12,608 = 12,608 : x
2. Step 2: Convert to fraction form
   7,840/12,608 = 12,608/x
3. Step 3: Cross multiply
   7,840x = 12,608 × 12,608
4. Step 4: Simplify right side
   7,840x = 158,961,664
5. Step 5: Solve for x
   x = 158,961,664/7,840
6. Step 6: Final answer
   x = 20,275.72