Finding the Third Proportional to 12,489 and 18,667.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12,489 : 18,667.50 = 18,667.50 : x
2. Step 2: Convert to fraction form
   12,489/18,667.50 = 18,667.50/x
3. Step 3: Cross multiply
   12,489x = 18,667.50 × 18,667.50
4. Step 4: Simplify right side
   12,489x = 348,475,556.25
5. Step 5: Solve for x
   x = 348,475,556.25/12,489
6. Step 6: Final answer
   x = 27,902.60