Finding the Fourth Proportional to 1,288.78, 1,933.71 and 712.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.78 : 1,933.71 = 712.06 : x
2. Step 2: Convert to fraction form
   1,288.78/1,933.71 = 712.06/x
3. Step 3: Cross multiply
   1,288.78x = 1,933.71 × 712.06
4. Step 4: Simplify right side
   1,288.78x = 1,376,917.54
5. Step 5: Solve for x
   x = 1,376,917.54/1,288.78
6. Step 6: Final answer
   x = 1,068.39