Finding the Third Proportional to 139,128 and 300,000

Step by Step Solution

1. Step 1: Write the proportion equation
   139,128 : 300,000 = 300,000 : x
2. Step 2: Convert to fraction form
   139,128/300,000 = 300,000/x
3. Step 3: Cross multiply
   139,128x = 300,000 × 300,000
4. Step 4: Simplify right side
   139,128x = 90,000,000,000
5. Step 5: Solve for x
   x = 90,000,000,000/139,128
6. Step 6: Final answer
   x = 646,886.32