Finding the Third Proportional to 121,039.50 and 258,756

Step by Step Solution

1. Step 1: Write the proportion equation
   121,039.50 : 258,756 = 258,756 : x
2. Step 2: Convert to fraction form
   121,039.50/258,756 = 258,756/x
3. Step 3: Cross multiply
   121,039.50x = 258,756 × 258,756
4. Step 4: Simplify right side
   121,039.50x = 66,954,667,536
5. Step 5: Solve for x
   x = 66,954,667,536/121,039.50
6. Step 6: Final answer
   x = 553,163.78