Finding the Fourth Proportional to 56.69, 78.25 and 42.18

Step by Step Solution

1. Step 1: Write the proportion equation
   56.69 : 78.25 = 42.18 : x
2. Step 2: Convert to fraction form
   56.69/78.25 = 42.18/x
3. Step 3: Cross multiply
   56.69x = 78.25 × 42.18
4. Step 4: Simplify right side
   56.69x = 3,299.98
5. Step 5: Solve for x
   x = 3,299.98/56.69
6. Step 6: Final answer
   x = 58.21