Finding the Fourth Proportional to 90.05, 134.91 and 53.91

Step by Step Solution

1. Step 1: Write the proportion equation
   90.05 : 134.91 = 53.91 : x
2. Step 2: Convert to fraction form
   90.05/134.91 = 53.91/x
3. Step 3: Cross multiply
   90.05x = 134.91 × 53.91
4. Step 4: Simplify right side
   90.05x = 7,273.00
5. Step 5: Solve for x
   x = 7,273.00/90.05
6. Step 6: Final answer
   x = 80.77