Finding the Fourth Proportional to 1,377.72, 1,900.80 and 853.92

Step by Step Solution

1. Step 1: Write the proportion equation
   1,377.72 : 1,900.80 = 853.92 : x
2. Step 2: Convert to fraction form
   1,377.72/1,900.80 = 853.92/x
3. Step 3: Cross multiply
   1,377.72x = 1,900.80 × 853.92
4. Step 4: Simplify right side
   1,377.72x = 1,623,131.14
5. Step 5: Solve for x
   x = 1,623,131.14/1,377.72
6. Step 6: Final answer
   x = 1,178.13