Finding the Fourth Proportional to 89.40, 123.12 and 89.13

Step by Step Solution

1. Step 1: Write the proportion equation
   89.40 : 123.12 = 89.13 : x
2. Step 2: Convert to fraction form
   89.40/123.12 = 89.13/x
3. Step 3: Cross multiply
   89.40x = 123.12 × 89.13
4. Step 4: Simplify right side
   89.40x = 10,973.69
5. Step 5: Solve for x
   x = 10,973.69/89.40
6. Step 6: Final answer
   x = 122.75