Unit 9 Section 1 : 2-D Shapes

The following table gives the names of some 2-D shapes. In this section we will consider the properties of some of these shapes.

Rectangle		All angles are right angles (90°) Opposite sides have the same length
Square		the same length All angles are right angles (90°)
Parallelogram		Opposite sides have the same length
Rhombus		All the sides have the same length Diagonals bisect at right angles
Trapezium
Kite		Diagonals intersect at right angles
Isosceles Triangle		Two sides have the same length and the angles opposite these two sides are equal
Equilateral Triangle		All angles are 60°

Example 1

Draw the lines of symmetry of an equilateral triangle.

There are 3 lines of symmetry, as shown in the diagram. They join each vertex (corner) to the midpoint of the opposite side.

Name each of the following shapes:

(a)

This is a rhombus because all the sides have the same lengths.

(b)

This is an isosceles triangle because two of the angles are the same size.

State the order of rotational symmetry of:

(a)	a trapezium,	1
(b)	a parallelogram.	2 (unless the parallelogram happens to be a square, in which case the order of rotational symmetry would be 4).

Question 1

Name each of the following shapes:

Question 4

State whether each of the following statements is true or false.

(a)	A square is also a rhombus.
(b)	A square is also a kite.
(c)	A rectangle is also a kite.
(d)	A parallelogram is also a kite.
(e)	A rectangle is also a parallelogram.

Question 5

Write down the order of rotational symmetry of: