Finding the Fourth Proportional to 89.94, 134.61 and 78.47

Step by Step Solution

1. Step 1: Write the proportion equation
   89.94 : 134.61 = 78.47 : x
2. Step 2: Convert to fraction form
   89.94/134.61 = 78.47/x
3. Step 3: Cross multiply
   89.94x = 134.61 × 78.47
4. Step 4: Simplify right side
   89.94x = 10,562.85
5. Step 5: Solve for x
   x = 10,562.85/89.94
6. Step 6: Final answer
   x = 117.44