Finding the Fourth Proportional to 89.91, 123.71 and 77.58

Step by Step Solution

1. Step 1: Write the proportion equation
   89.91 : 123.71 = 77.58 : x
2. Step 2: Convert to fraction form
   89.91/123.71 = 77.58/x
3. Step 3: Cross multiply
   89.91x = 123.71 × 77.58
4. Step 4: Simplify right side
   89.91x = 9,597.03
5. Step 5: Solve for x
   x = 9,597.03/89.91
6. Step 6: Final answer
   x = 106.74