We are given a triangle with two known angles: $35^\circ$ and $70^\circ$. The goal is to find the value of $x$, the third angle.

Steps:

1. The sum of the interior angles of any triangle is always $180^\circ$.

   $35^\circ + 70^\circ + x = 180^\circ$

2. Simplifying:

   $105^\circ + x = 180^\circ$

3. Subtract $105^\circ$ from both sides:

   $x = 180^\circ - 105^\circ$

4. Thus, $x = 75^\circ$.

Answer:

The value of $x$ is $75^\circ$, so the correct option is A.

Would you like further details or have any questions?

Here are 5 related questions:

1. How do you calculate the interior angles of any polygon?
2. What is the exterior angle theorem for triangles?
3. How do you classify triangles based on their angles?
4. What is the sum of interior angles in a quadrilateral?
5. How do you calculate angles in isosceles triangles?

Tip: Always remember that the sum of angles in any triangle is $180^\circ$.