Finding the Fourth Proportional to 28.61, 42.83 and 18.99

Step by Step Solution

1. Step 1: Write the proportion equation
   28.61 : 42.83 = 18.99 : x
2. Step 2: Convert to fraction form
   28.61/42.83 = 18.99/x
3. Step 3: Cross multiply
   28.61x = 42.83 × 18.99
4. Step 4: Simplify right side
   28.61x = 813.03
5. Step 5: Solve for x
   x = 813.03/28.61
6. Step 6: Final answer
   x = 28.42