Finding the Fourth Proportional to 1,111.88, 1,668.20 and 419.02

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.88 : 1,668.20 = 419.02 : x
2. Step 2: Convert to fraction form
   1,111.88/1,668.20 = 419.02/x
3. Step 3: Cross multiply
   1,111.88x = 1,668.20 × 419.02
4. Step 4: Simplify right side
   1,111.88x = 699,012.28
5. Step 5: Solve for x
   x = 699,012.28/1,111.88
6. Step 6: Final answer
   x = 628.68