Finding the Third Proportional to 148,618 and 320,456

Step by Step Solution

1. Step 1: Write the proportion equation
   148,618 : 320,456 = 320,456 : x
2. Step 2: Convert to fraction form
   148,618/320,456 = 320,456/x
3. Step 3: Cross multiply
   148,618x = 320,456 × 320,456
4. Step 4: Simplify right side
   148,618x = 102,692,047,936
5. Step 5: Solve for x
   x = 102,692,047,936/148,618
6. Step 6: Final answer
   x = 690,979.88