Finding the Fourth Proportional to 1,372.80, 1,894.59 and 783.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,372.80 : 1,894.59 = 783.57 : x
2. Step 2: Convert to fraction form
   1,372.80/1,894.59 = 783.57/x
3. Step 3: Cross multiply
   1,372.80x = 1,894.59 × 783.57
4. Step 4: Simplify right side
   1,372.80x = 1,484,543.89
5. Step 5: Solve for x
   x = 1,484,543.89/1,372.80
6. Step 6: Final answer
   x = 1,081.40