Finding the Fourth Proportional to 1,443.36, 1,991.84 and 780.22

Step by Step Solution

1. Step 1: Write the proportion equation
   1,443.36 : 1,991.84 = 780.22 : x
2. Step 2: Convert to fraction form
   1,443.36/1,991.84 = 780.22/x
3. Step 3: Cross multiply
   1,443.36x = 1,991.84 × 780.22
4. Step 4: Simplify right side
   1,443.36x = 1,554,063.45
5. Step 5: Solve for x
   x = 1,554,063.45/1,443.36
6. Step 6: Final answer
   x = 1,076.70