Finding the Fourth Proportional to 89.89, 134.36 and 78.23

Step by Step Solution

1. Step 1: Write the proportion equation
   89.89 : 134.36 = 78.23 : x
2. Step 2: Convert to fraction form
   89.89/134.36 = 78.23/x
3. Step 3: Cross multiply
   89.89x = 134.36 × 78.23
4. Step 4: Simplify right side
   89.89x = 10,510.42
5. Step 5: Solve for x
   x = 10,510.42/89.89
6. Step 6: Final answer
   x = 116.93