Finding the Fourth Proportional to 78.29, 108 and 67.91

Step by Step Solution

1. Step 1: Write the proportion equation
   78.29 : 108 = 67.91 : x
2. Step 2: Convert to fraction form
   78.29/108 = 67.91/x
3. Step 3: Cross multiply
   78.29x = 108 × 67.91
4. Step 4: Simplify right side
   78.29x = 7,334.55
5. Step 5: Solve for x
   x = 7,334.55/78.29
6. Step 6: Final answer
   x = 93.69