Finding the Fourth Proportional to 89.79, 123.71 and 83.31

Step by Step Solution

1. Step 1: Write the proportion equation
   89.79 : 123.71 = 83.31 : x
2. Step 2: Convert to fraction form
   89.79/123.71 = 83.31/x
3. Step 3: Cross multiply
   89.79x = 123.71 × 83.31
4. Step 4: Simplify right side
   89.79x = 10,305.86
5. Step 5: Solve for x
   x = 10,305.86/89.79
6. Step 6: Final answer
   x = 114.78