Finding the Fourth Proportional to 82.15, 113.42 and 63.69

Step by Step Solution

1. Step 1: Write the proportion equation
   82.15 : 113.42 = 63.69 : x
2. Step 2: Convert to fraction form
   82.15/113.42 = 63.69/x
3. Step 3: Cross multiply
   82.15x = 113.42 × 63.69
4. Step 4: Simplify right side
   82.15x = 7,223.72
5. Step 5: Solve for x
   x = 7,223.72/82.15
6. Step 6: Final answer
   x = 87.93