Finding the Third Proportional to 12,865.50 and 21,559.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12,865.50 : 21,559.50 = 21,559.50 : x
2. Step 2: Convert to fraction form
   12,865.50/21,559.50 = 21,559.50/x
3. Step 3: Cross multiply
   12,865.50x = 21,559.50 × 21,559.50
4. Step 4: Simplify right side
   12,865.50x = 464,812,040.25
5. Step 5: Solve for x
   x = 464,812,040.25/12,865.50
6. Step 6: Final answer
   x = 36,128.56