Finding the Fourth Proportional to 82.74, 123.96 and 42.18

Step by Step Solution

1. Step 1: Write the proportion equation
   82.74 : 123.96 = 42.18 : x
2. Step 2: Convert to fraction form
   82.74/123.96 = 42.18/x
3. Step 3: Cross multiply
   82.74x = 123.96 × 42.18
4. Step 4: Simplify right side
   82.74x = 5,228.63
5. Step 5: Solve for x
   x = 5,228.63/82.74
6. Step 6: Final answer
   x = 63.19