Finding the Third Proportional to 128,173.50 and 280,468.50

Step by Step Solution

1. Step 1: Write the proportion equation
   128,173.50 : 280,468.50 = 280,468.50 : x
2. Step 2: Convert to fraction form
   128,173.50/280,468.50 = 280,468.50/x
3. Step 3: Cross multiply
   128,173.50x = 280,468.50 × 280,468.50
4. Step 4: Simplify right side
   128,173.50x = 78,662,579,492.25
5. Step 5: Solve for x
   x = 78,662,579,492.25/128,173.50
6. Step 6: Final answer
   x = 613,719.52