Finding the Fourth Proportional to 1,238.78, 1,709.82 and 715.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,238.78 : 1,709.82 = 715.12 : x
2. Step 2: Convert to fraction form
   1,238.78/1,709.82 = 715.12/x
3. Step 3: Cross multiply
   1,238.78x = 1,709.82 × 715.12
4. Step 4: Simplify right side
   1,238.78x = 1,222,726.48
5. Step 5: Solve for x
   x = 1,222,726.48/1,238.78
6. Step 6: Final answer
   x = 987.04