The combined angle measure is 70^. The two given angles are 45^ and f^.

The value of $f$ is $\boxed{\text{25}}$.

4.
The combined angle measure is $115^\circ$. The two given angles are $t^\circ$ and $90^\circ$ (indicated by the right angle symbol).

The value of $t$ is $\boxed{\text{25}}$.

5.
The combined angle measure is $180^\circ$ (a straight angle). The two given angles are $x^\circ$ and $150^\circ$.

The value of $x$ is $\boxed{\text{30}}$.

6.
The two given angles, $35^\circ$ and $r^\circ$, form a right angle, which measures $90^\circ$.

The value of $r$ is $\boxed{\text{55}}$.

7. Problem Solving

A full circle is $360^\circ$, and there are 12 numbers on a clock.
Angle per number = $\frac{360^\circ}{12} = 30^\circ$.

The line is drawn to the number 12. The minute hand is on 2.

The minute hand moves 2 positions from 12 (from 12 to 1, and from 1 to 2).
Angle = $2 \times 30^\circ = 60^\circ$.
The angle is $\boxed{\text{60}^\circ}$.

8. Test Practice
The combined angle measure is $120^\circ$. The two given angles are $n^\circ$ and $80^\circ$.

The value of $n$ is 40.
Comparing this to the given options:
A) 45
B) 40
C) 35
D) 30
The correct option is B).