Triangles and polygons

Calculate:

1. A triangle has angles 50°, 60°. Find the third angle.
2. In isosceles triangle ABC, AB=AC and ∠BAC = 40°. Find ∠ABC.
3. Sum of interior angles of a pentagon.
4. Each exterior angle of a regular octagon.
5. Each interior angle of a regular hexagon.
6. A regular polygon has exterior angle 24°. How many sides?

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