Finding the Third Proportional to 8,418 and 17,990

Step by Step Solution

1. Step 1: Write the proportion equation
   8,418 : 17,990 = 17,990 : x
2. Step 2: Convert to fraction form
   8,418/17,990 = 17,990/x
3. Step 3: Cross multiply
   8,418x = 17,990 × 17,990
4. Step 4: Simplify right side
   8,418x = 323,640,100
5. Step 5: Solve for x
   x = 323,640,100/8,418
6. Step 6: Final answer
   x = 38,446.20