Finding the Fourth Proportional to 62.88, 86.76 and 42.15

Step by Step Solution

1. Step 1: Write the proportion equation
   62.88 : 86.76 = 42.15 : x
2. Step 2: Convert to fraction form
   62.88/86.76 = 42.15/x
3. Step 3: Cross multiply
   62.88x = 86.76 × 42.15
4. Step 4: Simplify right side
   62.88x = 3,656.93
5. Step 5: Solve for x
   x = 3,656.93/62.88
6. Step 6: Final answer
   x = 58.16