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

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

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

4. 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?

5. Angles in Quadrilaterals

6. 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°

7. 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?

8. 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°

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

10. 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.

12. Time for a real challenge!

13. 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

14. 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

15. 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

16. 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

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

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