Finding the Third Proportional to 120,868 and 256,144

Step by Step Solution

1. Step 1: Write the proportion equation
   120,868 : 256,144 = 256,144 : x
2. Step 2: Convert to fraction form
   120,868/256,144 = 256,144/x
3. Step 3: Cross multiply
   120,868x = 256,144 × 256,144
4. Step 4: Simplify right side
   120,868x = 65,609,748,736
5. Step 5: Solve for x
   x = 65,609,748,736/120,868
6. Step 6: Final answer
   x = 542,821.50