Finding the Fourth Proportional to 82.77, 124.07 and 42.15

Step by Step Solution

1. Step 1: Write the proportion equation
   82.77 : 124.07 = 42.15 : x
2. Step 2: Convert to fraction form
   82.77/124.07 = 42.15/x
3. Step 3: Cross multiply
   82.77x = 124.07 × 42.15
4. Step 4: Simplify right side
   82.77x = 5,228.72
5. Step 5: Solve for x
   x = 5,228.72/82.77
6. Step 6: Final answer
   x = 63.18