Page 63 - Ganit Kaushal

Activities

Activity 1

Using the concept of angle bisector through paper folding, make your protractor, starting with a semi-circular
transparent sheet (or paper sheet) of an appropriate radius.
Follow the steps:

Step 1: Write 0° at the bottom right and 180° at the bottom left of the half circular
sheet, as shown in the figure.

Step 2: Fold the half circular sheet again in half to form a quarter circle. Mark the
dotted line along the crease obtained. Then mark 90° at the top of it, as shown in the
figure.

Step 3: Further fold and unfold the sheet. Mark dotted lines along the crease. Mark
45° and 135° as shown in the adjacent figure.

Step 4: Continue with this process of folding and unfolding, and marking the
creases obtained. Unfold and mark the creases and mark the angle measure as
shown in the adjoining figures. This way, you will get your handmade protractor.
Step 5: Now, try to draw and measure a few angles with the help of this
handmade protractor.

Remark: Teachers should assist the students in this activity and are advised to explain the concept of bisecting
the angles and how it is used here in preparing this handmade protractor.

Activity 2: Drawing Angles with the Help of a Protractor

Draw a 30-degree angle and name it as TIN. Do as directed below:

1. First, draw the baseline and name it as IN.
2. Now, place the centre of the protractor at the point I
and align the line segment IN to the 0-degree line.

3. Now, starting from zero, count the degrees 10, 20,
and 30 on the protractor. Mark the point T at the
label 30 degrees, as shown in the picture.
4. Now, remove the protractor and join the line IT with
the help of a ruler. You will get the required angle, ∠TIN = 30°.
Similarly, make some other angles of your choice with the help of a protractor by following
the steps as mentioned above.

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