In any triangle the sum of the outer angles is 360 . What about a quadrilateral?

One angle of a triangle is equal to the sum of the other two angles of that triangle. The two smaller angles are in the ratio 2:3. What are the angles of triangle?

For the sequence of regular polygons starting with an equilateral triangle, write the algebraic expressions for the sequence of the sums of interior angles, the sums of the exterior angles, the measures of an interior angle, and the measures of an exterior angle.

Prove that in any triangle, the outer angle at a vertex is equal to the sum of the inner arigles at the outer two vertices.

The sum of the outer angles of a polygon is twice the sum of the inner angles. How many sides does it have? What if the sum of outer angles is half the sum of inner angles? And if the sums are equal?

In the figure, the line CE is parallel to BD. Area of triangle A B D is 30 sq.cm. and that of triangle BDC is 29 sq . cm. a) What is the area of quadrilateral ABCD? b) What is the area of triangle BED? c) What is the area of quadrilateral ABED?