Finding the Third Proportional to 128,806.50 and 279,790.50

Step by Step Solution

1. Step 1: Write the proportion equation
   128,806.50 : 279,790.50 = 279,790.50 : x
2. Step 2: Convert to fraction form
   128,806.50/279,790.50 = 279,790.50/x
3. Step 3: Cross multiply
   128,806.50x = 279,790.50 × 279,790.50
4. Step 4: Simplify right side
   128,806.50x = 78,282,723,890.25
5. Step 5: Solve for x
   x = 78,282,723,890.25/128,806.50
6. Step 6: Final answer
   x = 607,754.45