Finding the Third Proportional to 20,857.50 and 42,439.50

Step by Step Solution

1. Step 1: Write the proportion equation
   20,857.50 : 42,439.50 = 42,439.50 : x
2. Step 2: Convert to fraction form
   20,857.50/42,439.50 = 42,439.50/x
3. Step 3: Cross multiply
   20,857.50x = 42,439.50 × 42,439.50
4. Step 4: Simplify right side
   20,857.50x = 1,801,111,160.25
5. Step 5: Solve for x
   x = 1,801,111,160.25/20,857.50
6. Step 6: Final answer
   x = 86,353.17