Finding the Fourth Proportional to 76.59, 105.72 and 54.87

Step by Step Solution

1. Step 1: Write the proportion equation
   76.59 : 105.72 = 54.87 : x
2. Step 2: Convert to fraction form
   76.59/105.72 = 54.87/x
3. Step 3: Cross multiply
   76.59x = 105.72 × 54.87
4. Step 4: Simplify right side
   76.59x = 5,800.86
5. Step 5: Solve for x
   x = 5,800.86/76.59
6. Step 6: Final answer
   x = 75.74