Finding the Third Proportional to 8,439 and 12,290.25

Step by Step Solution

1. Step 1: Write the proportion equation
   8,439 : 12,290.25 = 12,290.25 : x
2. Step 2: Convert to fraction form
   8,439/12,290.25 = 12,290.25/x
3. Step 3: Cross multiply
   8,439x = 12,290.25 × 12,290.25
4. Step 4: Simplify right side
   8,439x = 151,050,245.06
5. Step 5: Solve for x
   x = 151,050,245.06/8,439
6. Step 6: Final answer
   x = 17,899.07