Finding the Fourth Proportional to 1,667.78, 2,301.67 and 921.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,667.78 : 2,301.67 = 921.81 : x
2. Step 2: Convert to fraction form
   1,667.78/2,301.67 = 921.81/x
3. Step 3: Cross multiply
   1,667.78x = 2,301.67 × 921.81
4. Step 4: Simplify right side
   1,667.78x = 2,121,702.42
5. Step 5: Solve for x
   x = 2,121,702.42/1,667.78
6. Step 6: Final answer
   x = 1,272.17