Finding the Third Proportional to 13,639.50 and 20,580.50

Step by Step Solution

1. Step 1: Write the proportion equation
   13,639.50 : 20,580.50 = 20,580.50 : x
2. Step 2: Convert to fraction form
   13,639.50/20,580.50 = 20,580.50/x
3. Step 3: Cross multiply
   13,639.50x = 20,580.50 × 20,580.50
4. Step 4: Simplify right side
   13,639.50x = 423,556,980.25
5. Step 5: Solve for x
   x = 423,556,980.25/13,639.50
6. Step 6: Final answer
   x = 31,053.70