Finding the Third Proportional to 243,146 and 390,667

Step by Step Solution

1. Step 1: Write the proportion equation
   243,146 : 390,667 = 390,667 : x
2. Step 2: Convert to fraction form
   243,146/390,667 = 390,667/x
3. Step 3: Cross multiply
   243,146x = 390,667 × 390,667
4. Step 4: Simplify right side
   243,146x = 152,620,704,889
5. Step 5: Solve for x
   x = 152,620,704,889/243,146
6. Step 6: Final answer
   x = 627,691.61