Finding the Fourth Proportional to 89.79, 123.65 and 82.05

Step by Step Solution

1. Step 1: Write the proportion equation
   89.79 : 123.65 = 82.05 : x
2. Step 2: Convert to fraction form
   89.79/123.65 = 82.05/x
3. Step 3: Cross multiply
   89.79x = 123.65 × 82.05
4. Step 4: Simplify right side
   89.79x = 10,145.07
5. Step 5: Solve for x
   x = 10,145.07/89.79
6. Step 6: Final answer
   x = 112.99