This page is optimized for mobile devices, if you would prefer the desktop version just click here

3.16 Polygons (Page 2/2)

_____________________________________________________________________

DIFFERENCES

between rhombus and square

_____________________________________________________________________

17.2 From other groups of three. Follow the same instructions as for 17.1 but build a rectangle instead. If you press on a corner it will change into a parallelogram.

Now complete the table by comparing the rectangle with the parallelogram:

SIMILARITIES

between rectangle and parallelogram

_____________________________________________________________________

DIFFERENCES

between rectangle and parallelogram

_____________________________________________________________________

18. What do we call this geometric figure?

__________________________________________

19. Form groups of four. Your teacher will say who must do a, b, c, and d.

19.1 Discuss the similarities and differences between:

a) a rhombus and a kite;

b) a trapezium and a parallelogram;

c) a rectangle and a trapezium;

d) a kite and a trapezium.

19.2 Make a poster to explain the above and report back to the class.

20. Did you know?

In maths we say a figure / structure is rigid if it can keep its original form even though pressure is applied to one of its corners, e.g.

Not sturdy

Sturdy

20.1 Divide into pairs. Use cool drink straws and build any rigid structure. See if you can build the highest structure in the class!

20.2 TAKE NOTE!

A triangle is the only polygon that is rigid. It doesn’t change its form when pressure is applied to any of its corners.

Where, do you think, do engineers and builders regularly use triangles to ensure stability in their constructions?

_____________________________________________________________________

21. Time for self-assessment

Tick the applicable block..	Uncertain	Certain
I can explain what the following are:
a polygon	___	___
a convex polygon	___	___
a concave polygon	___	___
a regular polygon	___	___
an irregular polygon	___	___
I know the formula to determine / calculate the size of the angles of a regular polygon	___	___
I can point out the similarities between different geometric forms.	___	___
I can point out the differences between different geometric forms.	___	___
I can build a rigid construction with cool drink straws	___	___

Assessment

Learning Outcome 3: The learner will be able to describe and represent characteristics and relationships between two-dimensional shapes and three-dimensional objects in a variety of orientations and positions.

Assessment Standard 3.1: We know this when the learner recognises, visualises and names geometric figures and solids in natural and cultural forms and geometric settings, including those previously dealt with.

Learning Outcome 2: The learner will be able to recognise, describe and represent patterns and relationships, as well as to solve problems using algebraic language and skills.

Assessment Standard 2.3: We know this when the learner represents and uses relationships between variables in order to determine input and/or output values in a variety of ways.

<< Chapter < Page Page > Chapter >>

Read also:

OpenStax, Mathematics grade 7. OpenStax CNX. Sep 16, 2009 Download for free at http://cnx.org/content/col11075/1.1

Google Play and the Google Play logo are trademarks of Google Inc.