Finding the Fourth Proportional to 1,287.42, 1,776.63 and 1,007.94

Step by Step Solution

1. Step 1: Write the proportion equation
   1,287.42 : 1,776.63 = 1,007.94 : x
2. Step 2: Convert to fraction form
   1,287.42/1,776.63 = 1,007.94/x
3. Step 3: Cross multiply
   1,287.42x = 1,776.63 × 1,007.94
4. Step 4: Simplify right side
   1,287.42x = 1,790,736.44
5. Step 5: Solve for x
   x = 1,790,736.44/1,287.42
6. Step 6: Final answer
   x = 1,390.95