Finding the Third Proportional to 128,646 and 200,142

Step by Step Solution

1. Step 1: Write the proportion equation
   128,646 : 200,142 = 200,142 : x
2. Step 2: Convert to fraction form
   128,646/200,142 = 200,142/x
3. Step 3: Cross multiply
   128,646x = 200,142 × 200,142
4. Step 4: Simplify right side
   128,646x = 40,056,820,164
5. Step 5: Solve for x
   x = 40,056,820,164/128,646
6. Step 6: Final answer
   x = 311,372.45