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.

Write the sum of the angles of an obtuse triangle.

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

Show that the sum of the three altitudes of a triangle is less than the sum of three sides of the triangle.

Show that the sum of the three altitudes of a triangle is less than the sum of three sides of the triangle.

Show that the sum of the three altitudes of a triangle is less than the sum of three sides of the triangle. GIVEN :triangle A B C in which A D_|_B C ,B E_|_A C and C F_|_A Bdot PROVE : A D+B E+C F < A B+B C+A C

Prove that measure of each angle of an equilateral triangle is 60^0dot

Prove that measure of each angle of an equilateral triangle is 60^0dot

Prove that the sum of two consecutive angles of a parallelogram is 180^(@).

Solve the following:(a) The teacher tells the class that the highest marks obtained by a student in her class is twice the lowest marks plus 7. The highest score is 87. What is the lowest score?(b) In an isosceles triangle, the base angles are equal. The vertex angle is 40°. What are the base angles of the triangle? (Remember, the sum of three angles of a triangle is 180°).