Finding the Fourth Proportional to 82.64, 114.56 and 78.72

Step by Step Solution

1. Step 1: Write the proportion equation
   82.64 : 114.56 = 78.72 : x
2. Step 2: Convert to fraction form
   82.64/114.56 = 78.72/x
3. Step 3: Cross multiply
   82.64x = 114.56 × 78.72
4. Step 4: Simplify right side
   82.64x = 9,018.16
5. Step 5: Solve for x
   x = 9,018.16/82.64
6. Step 6: Final answer
   x = 109.13