Finding the Fourth Proportional to 85.89, 118.35 and 65.10

Step by Step Solution

1. Step 1: Write the proportion equation
   85.89 : 118.35 = 65.10 : x
2. Step 2: Convert to fraction form
   85.89/118.35 = 65.10/x
3. Step 3: Cross multiply
   85.89x = 118.35 × 65.10
4. Step 4: Simplify right side
   85.89x = 7,704.59
5. Step 5: Solve for x
   x = 7,704.59/85.89
6. Step 6: Final answer
   x = 89.70