Finding the Third Proportional to 2.56 and 3.98

Step by Step Solution

1. Step 1: Write the proportion equation
   2.56 : 3.98 = 3.98 : x
2. Step 2: Convert to fraction form
   2.56/3.98 = 3.98/x
3. Step 3: Cross multiply
   2.56x = 3.98 × 3.98
4. Step 4: Simplify right side
   2.56x = 15.82
5. Step 5: Solve for x
   x = 15.82/2.56
6. Step 6: Final answer
   x = 6.18