Finding the Third Proportional to 0.78 and 1.69

Step by Step Solution

1. Step 1: Write the proportion equation
   0.78 : 1.69 = 1.69 : x
2. Step 2: Convert to fraction form
   0.78/1.69 = 1.69/x
3. Step 3: Cross multiply
   0.78x = 1.69 × 1.69
4. Step 4: Simplify right side
   0.78x = 2.85
5. Step 5: Solve for x
   x = 2.85/0.78
6. Step 6: Final answer
   x = 3.65