Finding the Third Proportional to 2,128.78 and 3,239.16

Step by Step Solution

1. Step 1: Write the proportion equation
   2,128.78 : 3,239.16 = 3,239.16 : x
2. Step 2: Convert to fraction form
   2,128.78/3,239.16 = 3,239.16/x
3. Step 3: Cross multiply
   2,128.78x = 3,239.16 × 3,239.16
4. Step 4: Simplify right side
   2,128.78x = 10,492,133.21
5. Step 5: Solve for x
   x = 10,492,133.21/2,128.78
6. Step 6: Final answer
   x = 4,928.70