Finding the Third Proportional to 12,879 and 20,178

Step by Step Solution

1. Step 1: Write the proportion equation
   12,879 : 20,178 = 20,178 : x
2. Step 2: Convert to fraction form
   12,879/20,178 = 20,178/x
3. Step 3: Cross multiply
   12,879x = 20,178 × 20,178
4. Step 4: Simplify right side
   12,879x = 407,151,684
5. Step 5: Solve for x
   x = 407,151,684/12,879
6. Step 6: Final answer
   x = 31,613.61