Finding the Third Proportional to 189,648 and 405,216

Step by Step Solution

1. Step 1: Write the proportion equation
   189,648 : 405,216 = 405,216 : x
2. Step 2: Convert to fraction form
   189,648/405,216 = 405,216/x
3. Step 3: Cross multiply
   189,648x = 405,216 × 405,216
4. Step 4: Simplify right side
   189,648x = 164,200,006,656
5. Step 5: Solve for x
   x = 164,200,006,656/189,648
6. Step 6: Final answer
   x = 865,814.60