Finding the Fourth Proportional to 1,390.82, 2,089.64 and 1,336.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.82 : 2,089.64 = 1,336.15 : x
2. Step 2: Convert to fraction form
   1,390.82/2,089.64 = 1,336.15/x
3. Step 3: Cross multiply
   1,390.82x = 2,089.64 × 1,336.15
4. Step 4: Simplify right side
   1,390.82x = 2,792,072.49
5. Step 5: Solve for x
   x = 2,792,072.49/1,390.82
6. Step 6: Final answer
   x = 2,007.50