Finding the Fourth Proportional to 89.78, 134.59 and 75.50

Step by Step Solution

1. Step 1: Write the proportion equation
   89.78 : 134.59 = 75.50 : x
2. Step 2: Convert to fraction form
   89.78/134.59 = 75.50/x
3. Step 3: Cross multiply
   89.78x = 134.59 × 75.50
4. Step 4: Simplify right side
   89.78x = 10,161.55
5. Step 5: Solve for x
   x = 10,161.55/89.78
6. Step 6: Final answer
   x = 113.18