Finding the Fourth Proportional to 86.72, 119.69 and 61.88

Step by Step Solution

1. Step 1: Write the proportion equation
   86.72 : 119.69 = 61.88 : x
2. Step 2: Convert to fraction form
   86.72/119.69 = 61.88/x
3. Step 3: Cross multiply
   86.72x = 119.69 × 61.88
4. Step 4: Simplify right side
   86.72x = 7,406.42
5. Step 5: Solve for x
   x = 7,406.42/86.72
6. Step 6: Final answer
   x = 85.41