Finding the Fourth Proportional to 85.82, 128.72 and 31.01

Step by Step Solution

1. Step 1: Write the proportion equation
   85.82 : 128.72 = 31.01 : x
2. Step 2: Convert to fraction form
   85.82/128.72 = 31.01/x
3. Step 3: Cross multiply
   85.82x = 128.72 × 31.01
4. Step 4: Simplify right side
   85.82x = 3,990.81
5. Step 5: Solve for x
   x = 3,990.81/85.82
6. Step 6: Final answer
   x = 46.50