Question

angle sum property of triangle​

Answer 1

Answer:

The Correct Answer is mentioned below

Step-by-step explanation:

The smallest polygon is the triangle, which has three sides and three internal angles. The internal angle sum property and the external angle property of a triangle will be covered in this article.

The total of a triangle's internal angles equals 180°, according to the angle sum property. The sum of the angles in every triangle, whether acute, obtuse, or right, will always be 180°. This can be expressed in the following way: A + B + C Equals 180° in an ABC triangle.

Answer 2

Answer:

The angle sum property of a triangle states that. The sum of the interior angles of a triangle is 180⁰

It could be proved like this

$\red{ \bold{to \: prove}} \\ \angle1 + \angle2 + \angle3 = 180 \degree$

Construction:

Draw DE || BC through A

$\angle4 = \angle2 \\ \angle5 = \angle3$

(angle 4,2 and angle 5,3 are alternate interior angles)

$\implies \: \angle1 + \angle2 + \angle3 = \angle4 + \angle5 + \angle6$

$\angle4 + \angle5 + \angle6 = 180 \degree$

(Because angles 4,5 and 6 are on a straight line)

$\tt{\bold{ \red{hence \: proved}}}$