Finding the Third Proportional to 128,410.50 and 199,611

Step by Step Solution

1. Step 1: Write the proportion equation
   128,410.50 : 199,611 = 199,611 : x
2. Step 2: Convert to fraction form
   128,410.50/199,611 = 199,611/x
3. Step 3: Cross multiply
   128,410.50x = 199,611 × 199,611
4. Step 4: Simplify right side
   128,410.50x = 39,844,551,321
5. Step 5: Solve for x
   x = 39,844,551,321/128,410.50
6. Step 6: Final answer
   x = 310,290.45