Finding the Third Proportional to 8,590 and 12,520.50

Step by Step Solution

1. Step 1: Write the proportion equation
   8,590 : 12,520.50 = 12,520.50 : x
2. Step 2: Convert to fraction form
   8,590/12,520.50 = 12,520.50/x
3. Step 3: Cross multiply
   8,590x = 12,520.50 × 12,520.50
4. Step 4: Simplify right side
   8,590x = 156,762,920.25
5. Step 5: Solve for x
   x = 156,762,920.25/8,590
6. Step 6: Final answer
   x = 18,249.47