Finding the Fourth Proportional to 89.42, 123.42 and 56.72

Step by Step Solution

1. Step 1: Write the proportion equation
   89.42 : 123.42 = 56.72 : x
2. Step 2: Convert to fraction form
   89.42/123.42 = 56.72/x
3. Step 3: Cross multiply
   89.42x = 123.42 × 56.72
4. Step 4: Simplify right side
   89.42x = 7,000.38
5. Step 5: Solve for x
   x = 7,000.38/89.42
6. Step 6: Final answer
   x = 78.29