Finding the Third Proportional to 189,439 and 405,144

Step by Step Solution

1. Step 1: Write the proportion equation
   189,439 : 405,144 = 405,144 : x
2. Step 2: Convert to fraction form
   189,439/405,144 = 405,144/x
3. Step 3: Cross multiply
   189,439x = 405,144 × 405,144
4. Step 4: Simplify right side
   189,439x = 164,141,660,736
5. Step 5: Solve for x
   x = 164,141,660,736/189,439
6. Step 6: Final answer
   x = 866,461.82