Finding the Fourth Proportional to 82.91, 113.69 and 78.98

Step by Step Solution

1. Step 1: Write the proportion equation
   82.91 : 113.69 = 78.98 : x
2. Step 2: Convert to fraction form
   82.91/113.69 = 78.98/x
3. Step 3: Cross multiply
   82.91x = 113.69 × 78.98
4. Step 4: Simplify right side
   82.91x = 8,978.87
5. Step 5: Solve for x
   x = 8,978.87/82.91
6. Step 6: Final answer
   x = 108.29