Finding the Fourth Proportional to 108.69, 162.90 and 78.27

Step by Step Solution

1. Step 1: Write the proportion equation
   108.69 : 162.90 = 78.27 : x
2. Step 2: Convert to fraction form
   108.69/162.90 = 78.27/x
3. Step 3: Cross multiply
   108.69x = 162.90 × 78.27
4. Step 4: Simplify right side
   108.69x = 12,749.37
5. Step 5: Solve for x
   x = 12,749.37/108.69
6. Step 6: Final answer
   x = 117.31