Prove that the sum of the three angles of a triangle is `180^0dot`

We know that the sum of the interior angles of a triangle is 180^0 . Show that the sums of eth interior angles of polygons with 3,4,5,6, sides for an arithmetic progression. Find the sum of the interior angles of or a 21 sided polygon.

Prove that the sum of the three exterior angles of a triangle,formed by producing the sides in order,is 4 right angles.

Theorem 6.7 : The sum of the angles of a triangle is 180º

Which of the following statements are true (T) and which are false (F): Sum of the three angles of a triangle is 180^0 A triangle can have two right angles. All the angles of a triangle can be less than 60^0 All the angles of a triangle can be greater than 60^0 All the angles of a triangle can be equal to 60^0 A triangle can have two obtuse angles. A triangle can have at most one obtuse angles. In one angle of a triangle is obtuse, then it cannot be a right angled triangle. An exterior angle of a triangle is less than either of its interior opposite angles. An exterior angle of a triangle is equal to the sum of the two interior opposite angles. An exterior angle of a triangle is greater than the opposite interior angles

Which of the following statements are true (T) and which are false (F): Sum of the three angles of a triangle is 180^0 A triangle can have two right angles. All the angles of a triangle can be less than 60^0 All the angles of a triangle can be greater than 60^0 All the angles of a triangle can be equal to 60^0 A triangle can have two obtuse angles. A triangle can have at most one obtuse angles. In one angle of a triangle is obtuse, then it cannot be a right angled triangle. An exterior angle of a triangle is less than either of its interior opposite angles. An exterior angle of a triangle is equal to the sum of the two interior opposite angles. An exterior angle of a triangle is greater than the opposite interior angles

Express the following statements by equations : The sum of the degree measures of the three angles of a triangle is 180^@ . The measure of the 2nd angle is twice that of the 1st and exceeds the thrid angle by 40^@ .

State whether the following statement is true or false: The sum of the interior angles of a triangle is 180^@ .