Finding the Third Proportional to 128,940 and 200,070

Step by Step Solution

1. Step 1: Write the proportion equation
   128,940 : 200,070 = 200,070 : x
2. Step 2: Convert to fraction form
   128,940/200,070 = 200,070/x
3. Step 3: Cross multiply
   128,940x = 200,070 × 200,070
4. Step 4: Simplify right side
   128,940x = 40,028,004,900
5. Step 5: Solve for x
   x = 40,028,004,900/128,940
6. Step 6: Final answer
   x = 310,439.00