Finding the Third Proportional to 256,636 and 558,426

Step by Step Solution

1. Step 1: Write the proportion equation
   256,636 : 558,426 = 558,426 : x
2. Step 2: Convert to fraction form
   256,636/558,426 = 558,426/x
3. Step 3: Cross multiply
   256,636x = 558,426 × 558,426
4. Step 4: Simplify right side
   256,636x = 311,839,597,476
5. Step 5: Solve for x
   x = 311,839,597,476/256,636
6. Step 6: Final answer
   x = 1,215,104.65