Finding the Third Proportional to 243,133 and 390,648

Step by Step Solution

1. Step 1: Write the proportion equation
   243,133 : 390,648 = 390,648 : x
2. Step 2: Convert to fraction form
   243,133/390,648 = 390,648/x
3. Step 3: Cross multiply
   243,133x = 390,648 × 390,648
4. Step 4: Simplify right side
   243,133x = 152,605,859,904
5. Step 5: Solve for x
   x = 152,605,859,904/243,133
6. Step 6: Final answer
   x = 627,664.12