Finding the Fourth Proportional to 85.84, 128.50 and 55.34

Step by Step Solution

1. Step 1: Write the proportion equation
   85.84 : 128.50 = 55.34 : x
2. Step 2: Convert to fraction form
   85.84/128.50 = 55.34/x
3. Step 3: Cross multiply
   85.84x = 128.50 × 55.34
4. Step 4: Simplify right side
   85.84x = 7,111.37
5. Step 5: Solve for x
   x = 7,111.37/85.84
6. Step 6: Final answer
   x = 82.85