Finding the Fourth Proportional to 1,705.38, 2,557.71 and 780.33

Step by Step Solution

1. Step 1: Write the proportion equation
   1,705.38 : 2,557.71 = 780.33 : x
2. Step 2: Convert to fraction form
   1,705.38/2,557.71 = 780.33/x
3. Step 3: Cross multiply
   1,705.38x = 2,557.71 × 780.33
4. Step 4: Simplify right side
   1,705.38x = 1,995,857.84
5. Step 5: Solve for x
   x = 1,995,857.84/1,705.38
6. Step 6: Final answer
   x = 1,170.33