Draw a quadrilateral And another … On your whiteboards … Draw a quadrilateral And another …

Draw a trapezium And another … On your whiteboards … Draw a trapezium And another …

Draw a parallelogram And another … On your whiteboards … Draw a parallelogram And another …

On your whiteboards … Draw any quadrilateral Draw a line joining an opposite pair of vertices What do you notice? What shapes have you created? What can you say about their angles?

Angles in Quadrilaterals

Angles in a quadrilateral always add up to 360° 180° 180° 180° 180° 180° 180° The interior angles of the quadrilaterals are the same as the interior angles of the two triangles. 2 x 180 = 360° Angles in a quadrilateral always add up to 360°

On your whiteboards … Draw any quadrilateral Draw two diagonals joining the two opposite pairs of vertices What shapes have you created? What can you say about their angles?

Angles in a quadrilateral always add up to 360° 180° 180° 180° 180° 180° 180° 180° 180° 180° 180° 180° 180° The interior angles of the quadrilaterals are equal to the interior angles of the 4 triangles with the middle circle removed. 4 x 180 – 360 = 360° Angles in a quadrilateral always add up to 360°

Angles in a quadrilateral always add up to 360o ao bo co do Write a maths sentence for the diagram. And another

What are the missing angles? How do you know? Now finish the rest of the worksheet. Write a maths sentence each time you find a missing angle.

Time for a real challenge!

Parallelograms In parallelograms, opposite sides are parallel. This means we can trace and translate to find missing angles. 121° b What are all of the angles in the cross? c a

Parallelograms In parallelograms, opposite sides are parallel. This means we can trace and translate to find missing angles. 121° b What is angle b? How do you know? c a

Parallelograms In parallelograms, opposite sides are parallel. This means we can trace and translate to find missing angles. 121° b What is angle c? How do you know? c a

Parallelograms In parallelograms, opposite sides are parallel. This means we can trace and translate to find missing angles. 121° b What is angle a? How do you know? c a

Opposite angles in a parallelogram are equal What do angles a + b = ? ao bo bo ao

ABCD is a parallelogram. Work out the sizes of angles h and j Give reasons for your answers.