Finding the Third Proportional to 3,123 and 8,221.50

Step by Step Solution

1. Step 1: Write the proportion equation
   3,123 : 8,221.50 = 8,221.50 : x
2. Step 2: Convert to fraction form
   3,123/8,221.50 = 8,221.50/x
3. Step 3: Cross multiply
   3,123x = 8,221.50 × 8,221.50
4. Step 4: Simplify right side
   3,123x = 67,593,062.25
5. Step 5: Solve for x
   x = 67,593,062.25/3,123
6. Step 6: Final answer
   x = 21,643.63