Finding the Fourth Proportional to 6.77, 10.15 and 3.91

Step by Step Solution

1. Step 1: Write the proportion equation
   6.77 : 10.15 = 3.91 : x
2. Step 2: Convert to fraction form
   6.77/10.15 = 3.91/x
3. Step 3: Cross multiply
   6.77x = 10.15 × 3.91
4. Step 4: Simplify right side
   6.77x = 39.69
5. Step 5: Solve for x
   x = 39.69/6.77
6. Step 6: Final answer
   x = 5.86