Finding the Third Proportional to 12,420 and 26,689.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12,420 : 26,689.50 = 26,689.50 : x
2. Step 2: Convert to fraction form
   12,420/26,689.50 = 26,689.50/x
3. Step 3: Cross multiply
   12,420x = 26,689.50 × 26,689.50
4. Step 4: Simplify right side
   12,420x = 712,329,410.25
5. Step 5: Solve for x
   x = 712,329,410.25/12,420
6. Step 6: Final answer
   x = 57,353.41