Finding the Third Proportional to 18,616.50 and 19,831.50

Step by Step Solution

1. Step 1: Write the proportion equation
   18,616.50 : 19,831.50 = 19,831.50 : x
2. Step 2: Convert to fraction form
   18,616.50/19,831.50 = 19,831.50/x
3. Step 3: Cross multiply
   18,616.50x = 19,831.50 × 19,831.50
4. Step 4: Simplify right side
   18,616.50x = 393,288,392.25
5. Step 5: Solve for x
   x = 393,288,392.25/18,616.50
6. Step 6: Final answer
   x = 21,125.80