Finding the Third Proportional to 252,256 and 390,600

Step by Step Solution

1. Step 1: Write the proportion equation
   252,256 : 390,600 = 390,600 : x
2. Step 2: Convert to fraction form
   252,256/390,600 = 390,600/x
3. Step 3: Cross multiply
   252,256x = 390,600 × 390,600
4. Step 4: Simplify right side
   252,256x = 152,568,360,000
5. Step 5: Solve for x
   x = 152,568,360,000/252,256
6. Step 6: Final answer
   x = 604,815.58