Finding the Fourth Proportional to 71.10, 106.67 and 42.21

Step by Step Solution

1. Step 1: Write the proportion equation
   71.10 : 106.67 = 42.21 : x
2. Step 2: Convert to fraction form
   71.10/106.67 = 42.21/x
3. Step 3: Cross multiply
   71.10x = 106.67 × 42.21
4. Step 4: Simplify right side
   71.10x = 4,502.33
5. Step 5: Solve for x
   x = 4,502.33/71.10
6. Step 6: Final answer
   x = 63.32