Finding the Fourth Proportional to 1,111.49, 1,667.73 and 418.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.49 : 1,667.73 = 418.21 : x
2. Step 2: Convert to fraction form
   1,111.49/1,667.73 = 418.21/x
3. Step 3: Cross multiply
   1,111.49x = 1,667.73 × 418.21
4. Step 4: Simplify right side
   1,111.49x = 697,457.19
5. Step 5: Solve for x
   x = 697,457.19/1,111.49
6. Step 6: Final answer
   x = 627.50