Finding the Fourth Proportional to 1,778.84, 2,667.72 and 853.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,778.84 : 2,667.72 = 853.91 : x
2. Step 2: Convert to fraction form
   1,778.84/2,667.72 = 853.91/x
3. Step 3: Cross multiply
   1,778.84x = 2,667.72 × 853.91
4. Step 4: Simplify right side
   1,778.84x = 2,277,992.79
5. Step 5: Solve for x
   x = 2,277,992.79/1,778.84
6. Step 6: Final answer
   x = 1,280.61