Finding the Third Proportional to 6,939 and 12,123

Step by Step Solution

1. Step 1: Write the proportion equation
   6,939 : 12,123 = 12,123 : x
2. Step 2: Convert to fraction form
   6,939/12,123 = 12,123/x
3. Step 3: Cross multiply
   6,939x = 12,123 × 12,123
4. Step 4: Simplify right side
   6,939x = 146,967,129
5. Step 5: Solve for x
   x = 146,967,129/6,939
6. Step 6: Final answer
   x = 21,179.87