Finding the Fourth Proportional to 42.99, 64.51 and 18.94

Step by Step Solution

1. Step 1: Write the proportion equation
   42.99 : 64.51 = 18.94 : x
2. Step 2: Convert to fraction form
   42.99/64.51 = 18.94/x
3. Step 3: Cross multiply
   42.99x = 64.51 × 18.94
4. Step 4: Simplify right side
   42.99x = 1,221.82
5. Step 5: Solve for x
   x = 1,221.82/42.99
6. Step 6: Final answer
   x = 28.42