Finding the Third Proportional to 9,129 and 12,789

Step by Step Solution

1. Step 1: Write the proportion equation
   9,129 : 12,789 = 12,789 : x
2. Step 2: Convert to fraction form
   9,129/12,789 = 12,789/x
3. Step 3: Cross multiply
   9,129x = 12,789 × 12,789
4. Step 4: Simplify right side
   9,129x = 163,558,521
5. Step 5: Solve for x
   x = 163,558,521/9,129
6. Step 6: Final answer
   x = 17,916.37