Finding the Fourth Proportional to 76.63, 105.72 and 54.81

Step by Step Solution

1. Step 1: Write the proportion equation
   76.63 : 105.72 = 54.81 : x
2. Step 2: Convert to fraction form
   76.63/105.72 = 54.81/x
3. Step 3: Cross multiply
   76.63x = 105.72 × 54.81
4. Step 4: Simplify right side
   76.63x = 5,794.51
5. Step 5: Solve for x
   x = 5,794.51/76.63
6. Step 6: Final answer
   x = 75.62