Finding the Fourth Proportional to 89.91, 134.52 and 78.99

Step by Step Solution

1. Step 1: Write the proportion equation
   89.91 : 134.52 = 78.99 : x
2. Step 2: Convert to fraction form
   89.91/134.52 = 78.99/x
3. Step 3: Cross multiply
   89.91x = 134.52 × 78.99
4. Step 4: Simplify right side
   89.91x = 10,625.73
5. Step 5: Solve for x
   x = 10,625.73/89.91
6. Step 6: Final answer
   x = 118.18