how practically u prove that a triangle has 180 deree or sum of all the angles=180?

Question

mathematics

Answer 1

extend the three sides of a triangle to form three external angles. These three sides extended form three straight angles or 180° each
180*3=540. But the external angles form a rotation of 360°. 540-360=180 for the three internal angles.

Answer 2

To physically demonstrate this, cut out any triangle you like from paper or cardboard. Cut off each corner. Arrange the corners so the points all meet.

Notice that the three corners, when aligned, add up to 180 degrees which shows up as a straight line (angle of 180 degrees).

For a more formal proof, see the link.

Answer 3

I don't know how practical this is, but it's a good physical demonstration. Cut out any triangle of paper. Then cut it into three pieces so that a corner is in each piece. Then, arrange the corners point to point to form a straight line across. You would be adding the three angles together to make 180.

Answer 4

Consider a right triangle; 90 + 45 + 45 = 180

A square's angles add to 360 (90x4), and 2 triangles can fit perfectly inside a sqaure.

Or an isocolese triangle; 60 + 60 + 60 = 180

Answer 5

Make a diagram.
Through the apex of a triangle draw a line paralel to the base.
Extend the sides.
Show that the three angles equal the angles of the triangle.

The angle of a line is half a circle or 180 degrees.

Answer 6

You add the degrees of each angle. add the three numbers.