Finding the Third Proportional to 128,409.50 and 199,608

Step by Step Solution

1. Step 1: Write the proportion equation
   128,409.50 : 199,608 = 199,608 : x
2. Step 2: Convert to fraction form
   128,409.50/199,608 = 199,608/x
3. Step 3: Cross multiply
   128,409.50x = 199,608 × 199,608
4. Step 4: Simplify right side
   128,409.50x = 39,843,353,664
5. Step 5: Solve for x
   x = 39,843,353,664/128,409.50
6. Step 6: Final answer
   x = 310,283.54