Finding the Fourth Proportional to 28.69, 42.86 and 18.98

Step by Step Solution

1. Step 1: Write the proportion equation
   28.69 : 42.86 = 18.98 : x
2. Step 2: Convert to fraction form
   28.69/42.86 = 18.98/x
3. Step 3: Cross multiply
   28.69x = 42.86 × 18.98
4. Step 4: Simplify right side
   28.69x = 813.50
5. Step 5: Solve for x
   x = 813.50/28.69
6. Step 6: Final answer
   x = 28.36