Finding the Third Proportional to 128,776.50 and 280,606.50

Step by Step Solution

1. Step 1: Write the proportion equation
   128,776.50 : 280,606.50 = 280,606.50 : x
2. Step 2: Convert to fraction form
   128,776.50/280,606.50 = 280,606.50/x
3. Step 3: Cross multiply
   128,776.50x = 280,606.50 × 280,606.50
4. Step 4: Simplify right side
   128,776.50x = 78,740,007,842.25
5. Step 5: Solve for x
   x = 78,740,007,842.25/128,776.50
6. Step 6: Final answer
   x = 611,447.03