Finding the Third Proportional to 10,690 and 12,178

Step by Step Solution

1. Step 1: Write the proportion equation
   10,690 : 12,178 = 12,178 : x
2. Step 2: Convert to fraction form
   10,690/12,178 = 12,178/x
3. Step 3: Cross multiply
   10,690x = 12,178 × 12,178
4. Step 4: Simplify right side
   10,690x = 148,303,684
5. Step 5: Solve for x
   x = 148,303,684/10,690
6. Step 6: Final answer
   x = 13,873.12