To solve for $x$ in the triangle, we can use the property that the sum of the angles in a triangle is always 180°.

We are given two angles:

• One angle is 39°.
• Another angle is 105°.

Let's find $x$:

$x = 180^\circ - (39^\circ + 105^\circ)$

$x = 180^\circ - 144^\circ = 36^\circ$

So, the value of $x$ is $36^\circ$.

Would you like a detailed explanation, or do you have any questions about this solution?

Here are five related questions to deepen your understanding:

1. What is the sum of the interior angles of any triangle?
2. How would the solution change if one of the angles in the triangle was a right angle (90°)?
3. If one angle in a triangle is obtuse (greater than 90°), how does it affect the other two angles?
4. Can a triangle have more than one obtuse angle? Why or why not?
5. How can we check if the angles of a triangle form a valid triangle?

Tip: Always remember that the sum of angles in any triangle is 180°, no matter the type of triangle.