Finding the Third Proportional to 128,128.50 and 200,416.50

Step by Step Solution

1. Step 1: Write the proportion equation
   128,128.50 : 200,416.50 = 200,416.50 : x
2. Step 2: Convert to fraction form
   128,128.50/200,416.50 = 200,416.50/x
3. Step 3: Cross multiply
   128,128.50x = 200,416.50 × 200,416.50
4. Step 4: Simplify right side
   128,128.50x = 40,166,773,472.25
5. Step 5: Solve for x
   x = 40,166,773,472.25/128,128.50
6. Step 6: Final answer
   x = 313,488.20