Finding the Third Proportional to 320,178 and 690,012

Step by Step Solution

1. Step 1: Write the proportion equation
   320,178 : 690,012 = 690,012 : x
2. Step 2: Convert to fraction form
   320,178/690,012 = 690,012/x
3. Step 3: Cross multiply
   320,178x = 690,012 × 690,012
4. Step 4: Simplify right side
   320,178x = 476,116,560,144
5. Step 5: Solve for x
   x = 476,116,560,144/320,178
6. Step 6: Final answer
   x = 1,487,037.09