Finding the Third Proportional to 128,178.70 and 280,520.72

Step by Step Solution

1. Step 1: Write the proportion equation
   128,178.70 : 280,520.72 = 280,520.72 : x
2. Step 2: Convert to fraction form
   128,178.70/280,520.72 = 280,520.72/x
3. Step 3: Cross multiply
   128,178.70x = 280,520.72 × 280,520.72
4. Step 4: Simplify right side
   128,178.70x = 78,691,873,648.02
5. Step 5: Solve for x
   x = 78,691,873,648.02/128,178.70
6. Step 6: Final answer
   x = 613,923.15