Finding the Third Proportional to 12,988 and 20,690

Step by Step Solution

1. Step 1: Write the proportion equation
   12,988 : 20,690 = 20,690 : x
2. Step 2: Convert to fraction form
   12,988/20,690 = 20,690/x
3. Step 3: Cross multiply
   12,988x = 20,690 × 20,690
4. Step 4: Simplify right side
   12,988x = 428,076,100
5. Step 5: Solve for x
   x = 428,076,100/12,988
6. Step 6: Final answer
   x = 32,959.35