Finding the Third Proportional to 128,740.50 and 280,356

Step by Step Solution

1. Step 1: Write the proportion equation
   128,740.50 : 280,356 = 280,356 : x
2. Step 2: Convert to fraction form
   128,740.50/280,356 = 280,356/x
3. Step 3: Cross multiply
   128,740.50x = 280,356 × 280,356
4. Step 4: Simplify right side
   128,740.50x = 78,599,486,736
5. Step 5: Solve for x
   x = 78,599,486,736/128,740.50
6. Step 6: Final answer
   x = 610,526.50