Finding the Third Proportional to 120,109 and 278,019

Step by Step Solution

1. Step 1: Write the proportion equation
   120,109 : 278,019 = 278,019 : x
2. Step 2: Convert to fraction form
   120,109/278,019 = 278,019/x
3. Step 3: Cross multiply
   120,109x = 278,019 × 278,019
4. Step 4: Simplify right side
   120,109x = 77,294,564,361
5. Step 5: Solve for x
   x = 77,294,564,361/120,109
6. Step 6: Final answer
   x = 643,536.82