Finding the Fourth Proportional to 42.81, 64.23 and 42.72

Step by Step Solution

1. Step 1: Write the proportion equation
   42.81 : 64.23 = 42.72 : x
2. Step 2: Convert to fraction form
   42.81/64.23 = 42.72/x
3. Step 3: Cross multiply
   42.81x = 64.23 × 42.72
4. Step 4: Simplify right side
   42.81x = 2,743.91
5. Step 5: Solve for x
   x = 2,743.91/42.81
6. Step 6: Final answer
   x = 64.09