Finding the Fourth Proportional to 89.63, 123.56 and 86.79

Step by Step Solution

1. Step 1: Write the proportion equation
   89.63 : 123.56 = 86.79 : x
2. Step 2: Convert to fraction form
   89.63/123.56 = 86.79/x
3. Step 3: Cross multiply
   89.63x = 123.56 × 86.79
4. Step 4: Simplify right side
   89.63x = 10,723.77
5. Step 5: Solve for x
   x = 10,723.77/89.63
6. Step 6: Final answer
   x = 119.65