Finding the Fourth Proportional to 89.78, 134.49 and 43.99

Step by Step Solution

1. Step 1: Write the proportion equation
   89.78 : 134.49 = 43.99 : x
2. Step 2: Convert to fraction form
   89.78/134.49 = 43.99/x
3. Step 3: Cross multiply
   89.78x = 134.49 × 43.99
4. Step 4: Simplify right side
   89.78x = 5,916.22
5. Step 5: Solve for x
   x = 5,916.22/89.78
6. Step 6: Final answer
   x = 65.90