1. **State the problem:** We need to find the size of angle $c$ in a figure with two triangles sharing a middle segment, given angles $20^\circ$ and $62^\circ$, and two equal-length sides on the right.
2. **Analyze the figure:** The top line has a vertex near the middle, forming two triangles. The left top angle is $20^\circ$, the lower middle angle is $62^\circ$, and the two right segments are equal in length, indicating an isosceles triangle on the right.
3. **Use triangle angle sum rule:** The sum of angles in any triangle is $180^\circ$.
4. **Focus on the right triangle:** Since the two right segments are equal, the base angles opposite these sides are equal. Let each base angle be $c$.
5. **Calculate the third angle in the right triangle:** The angle adjacent to $c$ is $62^\circ$ (given). The sum of angles in this triangle is:
$$ 62^\circ + c + c = 180^\circ $$
6. **Simplify and solve for $c$:**
$$ 62^\circ + 2c = 180^\circ $$
$$ 2c = 180^\circ - 62^\circ $$
$$ 2c = 118^\circ $$
$$ c = \frac{118^\circ}{2} $$
$$ c = 59^\circ $$
7. **Final answer:** The size of angle $c$ is $59^\circ$.
Angle C B8979D
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