Finding the Third Proportional to 128,152.50 and 280,431

Step by Step Solution

1. Step 1: Write the proportion equation
   128,152.50 : 280,431 = 280,431 : x
2. Step 2: Convert to fraction form
   128,152.50/280,431 = 280,431/x
3. Step 3: Cross multiply
   128,152.50x = 280,431 × 280,431
4. Step 4: Simplify right side
   128,152.50x = 78,641,545,761
5. Step 5: Solve for x
   x = 78,641,545,761/128,152.50
6. Step 6: Final answer
   x = 613,655.96