Finding the Third Proportional to 5,123.25 and 12,129.75

Step by Step Solution

1. Step 1: Write the proportion equation
   5,123.25 : 12,129.75 = 12,129.75 : x
2. Step 2: Convert to fraction form
   5,123.25/12,129.75 = 12,129.75/x
3. Step 3: Cross multiply
   5,123.25x = 12,129.75 × 12,129.75
4. Step 4: Simplify right side
   5,123.25x = 147,130,835.06
5. Step 5: Solve for x
   x = 147,130,835.06/5,123.25
6. Step 6: Final answer
   x = 28,718.26