Teacher 1

TRIANGLES The activities are designed to support basic Geometry – in particular the properties and behaviour of particular triangles. SKETCHPAD WORKBOOKS There are two ways in which these tasks can be done. The first option is that each of these three tasks is completed in a separate file which can be electronically sent to the Teacher or printed out. In the second way, a single Sketchpad document is set up with a number of worksheets that can be accessed through tabs at the bottom of the worksheet (similar to those on spreadsheets). In this way only a single document is received from each student. The procedure for setting this up is given below. SETTING UP A GEOMETER’S SKETCHPAD WORKBOOK 1. Click on The Geometer’s Sketchpad icon in the dock to start the program. 2. On the FILE Menu, select SAVE. Name it (initial)(surname)(form). 3. On the FILE Menu, select DOCUMENT OPTIONS. In the window that opens, enter “T1” for the PAGE NAME and click on the SHOW PAGE TABS button. 4. Click on the ADD PAGE bar, and select BLANK PAGE. Name this new page T2. (Note that you can now see tabs for T1 and T2 at the bottom of the worksheet.) 5. Repeat step 4. twice more to add pages labeled T3A and T3B. 6. Now click OK. 7. On the FILE Menu, select SAVE to save your workbook. (The extra worksheets for Task 3 are because there are more than four (4) triangles to be constructed.) Students now complete each Task on the appropriate numbered worksheet. A pro forma Answer Sheet has been provided for students to complete as they proceed through the tasks set. Tasks 1 – 3 can be assessed both on the printouts and the work presented on the Answer Sheet. You may wish to discuss or demonstrate why certain combinations are not possible for Task 3 (based on the Answer Sheet activity). REMIND STUDENTS TO SAVE FREQUENTLY DURING THE CLASS ACTIVITIES.

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COMMENTS ON THE TASKS TASK 1 Students are required to create the three triangles based on side measurements only – the Answer Sheet section gives hints as to the names, and could be done as a class activity as preparation for the drawings. Students should position the three triangles so that they can be printed out on ONE sheet of A4 paper. If you are assessing electronically, then the close positioning should enable easier viewing of the completed work. (i) Equilateral (ii) Isosceles (iii) Scalene

ALL sides have the SAME length TWO sides have the SAME length ALL sides have DIFFERENT lengths

TASK 2 Students are required to create the three triangles based on angle measurements only – the Answer Sheet section gives hints as to the names, and could be done as a class activity as preparation for the drawings. Students should position the three triangles so that they can be printed out on ONE sheet of A4 paper. (i) Obtuse (ii) Acute (iii) Right

ONE angle in the triangle is GREATER than 90˚ ALL angles in the triangle are LESS than 90˚ ONE angle in the triangle is EQUAL to 90˚

TASK 3 Students are required to create as many triangles as possible based on a combination of angle and side measurements. The Plan must be completed and inspected by you PRIOR to the students commencing work. As there are seven (7) possible triangles, they will need to split them between page 3A and page 3B, with four (4) on one page and three (3) on the other. Students should position the triangles on each page so that each set can be printed out on ONE sheet of A4 paper. Triangle Name Equilateral Acute Equilateral Obtuse Equilateral Right Isosceles Acute Isosceles Obtuse Isosceles Right Scalene Acute Scalene Obtuse Scalene Right

Constructable ? YES NO NO YES YES YES YES YES YES

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