Finding the Third Proportional to 12,720.50 and 19,719.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12,720.50 : 19,719.50 = 19,719.50 : x
2. Step 2: Convert to fraction form
   12,720.50/19,719.50 = 19,719.50/x
3. Step 3: Cross multiply
   12,720.50x = 19,719.50 × 19,719.50
4. Step 4: Simplify right side
   12,720.50x = 388,858,680.25
5. Step 5: Solve for x
   x = 388,858,680.25/12,720.50
6. Step 6: Final answer
   x = 30,569.45