Finding the Third Proportional to 111,409 and 256,519

Step by Step Solution

1. Step 1: Write the proportion equation
   111,409 : 256,519 = 256,519 : x
2. Step 2: Convert to fraction form
   111,409/256,519 = 256,519/x
3. Step 3: Cross multiply
   111,409x = 256,519 × 256,519
4. Step 4: Simplify right side
   111,409x = 65,801,997,361
5. Step 5: Solve for x
   x = 65,801,997,361/111,409
6. Step 6: Final answer
   x = 590,634.49