Everything Maths Grade 10

Investigation: Interior angles of a triangle

b

a

c

1.On a piece of paper draw a triangle of any size and shape.

2.Cut it out and label the angles^a,^band^con both sides of the paper.

3.Draw dotted lines as shown and cut along these lines to get three pieces of paper.

4.Place them along your ruler as shown in the figure below.

5.What can we conclude?

Hint: What is the sum of angles on a straight line?

a bc

Investigation: Exterior angles of a triangle

b

a

c

1.On a piece of paper draw a triangle of any size and shape. On another piece of paper, make a copy of

the triangle.

2.Cut both out and label the angles of both triangles^a,^band^con both sides of the paper.

3.Draw dotted lines ononetriangle as shown and cut along the lines.

4.Place the second triangle and the cut out pieces as shown in the figure below.

5.What can we can conclude?

b

a

c

a

b

244 7.2. Triangles