Finding the Fourth Proportional to 89.68, 134.37 and 78.91

Step by Step Solution

1. Step 1: Write the proportion equation
   89.68 : 134.37 = 78.91 : x
2. Step 2: Convert to fraction form
   89.68/134.37 = 78.91/x
3. Step 3: Cross multiply
   89.68x = 134.37 × 78.91
4. Step 4: Simplify right side
   89.68x = 10,603.14
5. Step 5: Solve for x
   x = 10,603.14/89.68
6. Step 6: Final answer
   x = 118.23