Finding the Third Proportional to 12,840 and 28,128

Step by Step Solution

1. Step 1: Write the proportion equation
   12,840 : 28,128 = 28,128 : x
2. Step 2: Convert to fraction form
   12,840/28,128 = 28,128/x
3. Step 3: Cross multiply
   12,840x = 28,128 × 28,128
4. Step 4: Simplify right side
   12,840x = 791,184,384
5. Step 5: Solve for x
   x = 791,184,384/12,840
6. Step 6: Final answer
   x = 61,618.72