Finding the Fourth Proportional to 82.10, 123.16 and 45.54

Step by Step Solution

1. Step 1: Write the proportion equation
   82.10 : 123.16 = 45.54 : x
2. Step 2: Convert to fraction form
   82.10/123.16 = 45.54/x
3. Step 3: Cross multiply
   82.10x = 123.16 × 45.54
4. Step 4: Simplify right side
   82.10x = 5,608.71
5. Step 5: Solve for x
   x = 5,608.71/82.10
6. Step 6: Final answer
   x = 68.32