Finding the Third Proportional to 120,256 and 257,200

Step by Step Solution

1. Step 1: Write the proportion equation
   120,256 : 257,200 = 257,200 : x
2. Step 2: Convert to fraction form
   120,256/257,200 = 257,200/x
3. Step 3: Cross multiply
   120,256x = 257,200 × 257,200
4. Step 4: Simplify right side
   120,256x = 66,151,840,000
5. Step 5: Solve for x
   x = 66,151,840,000/120,256
6. Step 6: Final answer
   x = 550,091.80