Finding the Third Proportional to 128,177.50 and 280,478

Step by Step Solution

1. Step 1: Write the proportion equation
   128,177.50 : 280,478 = 280,478 : x
2. Step 2: Convert to fraction form
   128,177.50/280,478 = 280,478/x
3. Step 3: Cross multiply
   128,177.50x = 280,478 × 280,478
4. Step 4: Simplify right side
   128,177.50x = 78,667,908,484
5. Step 5: Solve for x
   x = 78,667,908,484/128,177.50
6. Step 6: Final answer
   x = 613,741.95