Finding the Fourth Proportional to 42.21, 63.36 and 42.09

Step by Step Solution

1. Step 1: Write the proportion equation
   42.21 : 63.36 = 42.09 : x
2. Step 2: Convert to fraction form
   42.21/63.36 = 42.09/x
3. Step 3: Cross multiply
   42.21x = 63.36 × 42.09
4. Step 4: Simplify right side
   42.21x = 2,666.82
5. Step 5: Solve for x
   x = 2,666.82/42.21
6. Step 6: Final answer
   x = 63.18