Finding the Third Proportional to 128,789.16 and 189,459

Step by Step Solution

1. Step 1: Write the proportion equation
   128,789.16 : 189,459 = 189,459 : x
2. Step 2: Convert to fraction form
   128,789.16/189,459 = 189,459/x
3. Step 3: Cross multiply
   128,789.16x = 189,459 × 189,459
4. Step 4: Simplify right side
   128,789.16x = 35,894,712,681
5. Step 5: Solve for x
   x = 35,894,712,681/128,789.16
6. Step 6: Final answer
   x = 278,709.12