Finding the Third Proportional to 10,617 and 12,987

Step by Step Solution

1. Step 1: Write the proportion equation
   10,617 : 12,987 = 12,987 : x
2. Step 2: Convert to fraction form
   10,617/12,987 = 12,987/x
3. Step 3: Cross multiply
   10,617x = 12,987 × 12,987
4. Step 4: Simplify right side
   10,617x = 168,662,169
5. Step 5: Solve for x
   x = 168,662,169/10,617
6. Step 6: Final answer
   x = 15,886.05