Finding the Fourth Proportional to 89.89, 124.06 and 57.15

Step by Step Solution

1. Step 1: Write the proportion equation
   89.89 : 124.06 = 57.15 : x
2. Step 2: Convert to fraction form
   89.89/124.06 = 57.15/x
3. Step 3: Cross multiply
   89.89x = 124.06 × 57.15
4. Step 4: Simplify right side
   89.89x = 7,090.03
5. Step 5: Solve for x
   x = 7,090.03/89.89
6. Step 6: Final answer
   x = 78.87