Finding the Fourth Proportional to 51.87, 71.58 and 42.15

Step by Step Solution

1. Step 1: Write the proportion equation
   51.87 : 71.58 = 42.15 : x
2. Step 2: Convert to fraction form
   51.87/71.58 = 42.15/x
3. Step 3: Cross multiply
   51.87x = 71.58 × 42.15
4. Step 4: Simplify right side
   51.87x = 3,017.10
5. Step 5: Solve for x
   x = 3,017.10/51.87
6. Step 6: Final answer
   x = 58.17