Finding the Third Proportional to 11,172 and 17,990

Step by Step Solution

1. Step 1: Write the proportion equation
   11,172 : 17,990 = 17,990 : x
2. Step 2: Convert to fraction form
   11,172/17,990 = 17,990/x
3. Step 3: Cross multiply
   11,172x = 17,990 × 17,990
4. Step 4: Simplify right side
   11,172x = 323,640,100
5. Step 5: Solve for x
   x = 323,640,100/11,172
6. Step 6: Final answer
   x = 28,968.86