Finding the Third Proportional to 13,387.50 and 20,431.50

Step by Step Solution

1. Step 1: Write the proportion equation
   13,387.50 : 20,431.50 = 20,431.50 : x
2. Step 2: Convert to fraction form
   13,387.50/20,431.50 = 20,431.50/x
3. Step 3: Cross multiply
   13,387.50x = 20,431.50 × 20,431.50
4. Step 4: Simplify right side
   13,387.50x = 417,446,192.25
5. Step 5: Solve for x
   x = 417,446,192.25/13,387.50
6. Step 6: Final answer
   x = 31,181.79