Finding the Fourth Proportional to 42.81, 58.68 and 42.21

Step by Step Solution

1. Step 1: Write the proportion equation
   42.81 : 58.68 = 42.21 : x
2. Step 2: Convert to fraction form
   42.81/58.68 = 42.21/x
3. Step 3: Cross multiply
   42.81x = 58.68 × 42.21
4. Step 4: Simplify right side
   42.81x = 2,476.88
5. Step 5: Solve for x
   x = 2,476.88/42.81
6. Step 6: Final answer
   x = 57.86