Finding the Fourth Proportional to 83.10, 113.94 and 77.10

Step by Step Solution

1. Step 1: Write the proportion equation
   83.10 : 113.94 = 77.10 : x
2. Step 2: Convert to fraction form
   83.10/113.94 = 77.10/x
3. Step 3: Cross multiply
   83.10x = 113.94 × 77.10
4. Step 4: Simplify right side
   83.10x = 8,784.83
5. Step 5: Solve for x
   x = 8,784.83/83.10
6. Step 6: Final answer
   x = 105.71