Finding the Fourth Proportional to 1,111.51, 1,667.26 and 289.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.51 : 1,667.26 = 289.78 : x
2. Step 2: Convert to fraction form
   1,111.51/1,667.26 = 289.78/x
3. Step 3: Cross multiply
   1,111.51x = 1,667.26 × 289.78
4. Step 4: Simplify right side
   1,111.51x = 483,128.82
5. Step 5: Solve for x
   x = 483,128.82/1,111.51
6. Step 6: Final answer
   x = 434.66