Finding the Fourth Proportional to 91.23, 136.89 and 42.56

Step by Step Solution

1. Step 1: Write the proportion equation
   91.23 : 136.89 = 42.56 : x
2. Step 2: Convert to fraction form
   91.23/136.89 = 42.56/x
3. Step 3: Cross multiply
   91.23x = 136.89 × 42.56
4. Step 4: Simplify right side
   91.23x = 5,825.87
5. Step 5: Solve for x
   x = 5,825.87/91.23
6. Step 6: Final answer
   x = 63.86