Lines of symmetry

Wala: Lines of symmetry

L.O:Identify lines of symmetry in 2-D shapes presented in different orientations.

Real life application of symmetry.

1. We use symmetry in social situations. We expect people to act the same in certain common circumstances. For example, my expectation of a barista behind the counter to take my order at a coffee shop no matter what style of hair they wear, no matter what the current weather is, no matter what I actually decide to order.

Real life application of symmetry.

We use symmetry in traffic. Despite all the different types of cars on the road and different types of people driving them, we expect cars to stop at red lights and stop signs. Using this symmetry, allows us to decide it’s safe to cross the street when the light is red for cross traffic.

Real life application of symmetry.

We use symmetry when interacting with (well-built) machines. When I insert my key and fully turn my car’s ignition, I expect the car to start. This does not depend on the location of my car, whether or not there’s rain

Any other real life application of symmetry?

Definition symmetry.

Symmetry is when one shape becomes exactly like another if you flip, slide or turn it.

A line of symmetry cuts a shape into two identical parts that mirror each other. In other words one side is a reflection of the other.

Folding Test

(http://www.mathsisfun.com/geometry/symmetry-line-plane-shapes.html)

Folding test.

You can find if a shape has a Line of Symmetry by folding it.

When the folded part sits perfectly on top (all edges matching), then the fold line is a Line of Symmetry.

Activity.

Folding Test.

ROOM 1

a) How many lines of symmetry does a rectangle have?

ROOM 2

a)How many lines of symmetry does an equilateral triangle have?

ROOM 3

How many lines of symmetry does a square have?

ROOM 4

How many lines of symmetry does a rhombus have?

Presentation.

Each group presents their finding through folding test.

Plenary.

1. What is symmetry?
2. How many sides and lines of symmetry does the following shapes have?

a) Square.

b) Rectangle.

c) Regular pentagon.

d) Equilateral triangle.

e) Isosceles triangle.

f) Scalene triangle