Using the sum of the interior angles of a triangle

Maths

This unit gives pupils the opportunity to explore polygons and begin to generalise their understanding of interior/exterior angles in regular polygons. In the future unit, pupils will use the geometrical properties of a rhombus to perform various constructions

In this unit, pupils learnt how to calculate with angles at a point and angles on a straight line. In this unit, pupils extend their knowledge about angles in lines

Geometrical properties: polygons

The size of the angle $$x$$° is {{ }}°.

Match the two angles of a triangle with its third angle.

In which of these triangles is there enough information for you to calculate the size of the missing angle? 

The size of the angle $$x°$$ is {{ }}°.

Which of the following are calculations to find the value of $$y$$?

Simplify the following expression $$3x+5y-2x+9y+3x+12$$.

A triangle DEF, where DE = 23 cm, DF = 23 cm and angle EDF is 45° is __________ triangle.

Which of these are correct for the size of the angle marked $$n$$?

...shown that the three angles in a triangle sum to 180°.

...demonstrated that the three angles in a triangle sum to 180°.

...proved that the three angles in a triangle sum to 180°.

Select the statements that best complete the following sentence. By tearing the corners off of a triangle and arranging them together at a point it you have... 

This lesson will soon be taken down.

Using the sum of the interior angles of a triangle

Lesson outcome