Finding the Third Proportional to 3,456 and 3,690

Step by Step Solution

1. Step 1: Write the proportion equation
   3,456 : 3,690 = 3,690 : x
2. Step 2: Convert to fraction form
   3,456/3,690 = 3,690/x
3. Step 3: Cross multiply
   3,456x = 3,690 × 3,690
4. Step 4: Simplify right side
   3,456x = 13,616,100
5. Step 5: Solve for x
   x = 13,616,100/3,456
6. Step 6: Final answer
   x = 3,939.84