Finding the Fourth Proportional to 76.99, 115.52 and 42.72

Step by Step Solution

1. Step 1: Write the proportion equation
   76.99 : 115.52 = 42.72 : x
2. Step 2: Convert to fraction form
   76.99/115.52 = 42.72/x
3. Step 3: Cross multiply
   76.99x = 115.52 × 42.72
4. Step 4: Simplify right side
   76.99x = 4,935.01
5. Step 5: Solve for x
   x = 4,935.01/76.99
6. Step 6: Final answer
   x = 64.10