Finding the Third Proportional to 8,426.50 and 12,991.25

Step by Step Solution

1. Step 1: Write the proportion equation
   8,426.50 : 12,991.25 = 12,991.25 : x
2. Step 2: Convert to fraction form
   8,426.50/12,991.25 = 12,991.25/x
3. Step 3: Cross multiply
   8,426.50x = 12,991.25 × 12,991.25
4. Step 4: Simplify right side
   8,426.50x = 168,772,576.56
5. Step 5: Solve for x
   x = 168,772,576.56/8,426.50
6. Step 6: Final answer
   x = 20,028.79