Finding the Third Proportional to 315,588 and 690,144

Step by Step Solution

1. Step 1: Write the proportion equation
   315,588 : 690,144 = 690,144 : x
2. Step 2: Convert to fraction form
   315,588/690,144 = 690,144/x
3. Step 3: Cross multiply
   315,588x = 690,144 × 690,144
4. Step 4: Simplify right side
   315,588x = 476,298,740,736
5. Step 5: Solve for x
   x = 476,298,740,736/315,588
6. Step 6: Final answer
   x = 1,509,242.24