Finding the Fourth Proportional to 76.55, 105.64 and 42.05

Step by Step Solution

1. Step 1: Write the proportion equation
   76.55 : 105.64 = 42.05 : x
2. Step 2: Convert to fraction form
   76.55/105.64 = 42.05/x
3. Step 3: Cross multiply
   76.55x = 105.64 × 42.05
4. Step 4: Simplify right side
   76.55x = 4,441.42
5. Step 5: Solve for x
   x = 4,441.42/76.55
6. Step 6: Final answer
   x = 58.02