Finding the Fourth Proportional to 1,111.94, 1,667.87 and 290.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.94 : 1,667.87 = 290.21 : x
2. Step 2: Convert to fraction form
   1,111.94/1,667.87 = 290.21/x
3. Step 3: Cross multiply
   1,111.94x = 1,667.87 × 290.21
4. Step 4: Simplify right side
   1,111.94x = 484,022.76
5. Step 5: Solve for x
   x = 484,022.76/1,111.94
6. Step 6: Final answer
   x = 435.30