Finding the Fourth Proportional to 91.23, 136.16 and 78.27

Step by Step Solution

1. Step 1: Write the proportion equation
   91.23 : 136.16 = 78.27 : x
2. Step 2: Convert to fraction form
   91.23/136.16 = 78.27/x
3. Step 3: Cross multiply
   91.23x = 136.16 × 78.27
4. Step 4: Simplify right side
   91.23x = 10,656.85
5. Step 5: Solve for x
   x = 10,656.85/91.23
6. Step 6: Final answer
   x = 116.81