Finding the Fourth Proportional to 42.77, 64.16 and 15.71

Step by Step Solution

1. Step 1: Write the proportion equation
   42.77 : 64.16 = 15.71 : x
2. Step 2: Convert to fraction form
   42.77/64.16 = 15.71/x
3. Step 3: Cross multiply
   42.77x = 64.16 × 15.71
4. Step 4: Simplify right side
   42.77x = 1,007.55
5. Step 5: Solve for x
   x = 1,007.55/42.77
6. Step 6: Final answer
   x = 23.56