Foundations 20 – Sums of Angles
Name: _______________________________
Date: ________________________________
Sums of Angles
In this lesson we will be investigating the sums of the interior angles of various polygons.
Part 1: Triangles (3 Sided Polygons)
a) Draw 3 different triangles.
b) Measure the lengths of the interior angles, and record them in the table below.
Triangle 1
Triangle 2
Triangle 3
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Foundations 20 – Sums of Angles
c) Find the sum of the 3 interior angles.
Triangle 1:
Triangle 2:
Triangle 3:
d) What do you notice?
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Foundations 20 – Sums of Angles
Part 2: Four Sided Polygons
a) Draw 3 different four sided polygons. (Be creative with the shape.)
b) Measure the lengths of the interior angles, and record them in the table below.
Polygon 1
Polygon 2
Polygon 3
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Foundations 20 – Sums of Angles
c) Find the sum of the 4 interior angles.
Polygon 1:
Polygon 2:
Polygon 3:
d) What do you notice?
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Foundations 20 – Sums of Angles
Part 3: Five Sided Polygons
a) Draw 3 different five sided polygons. (Be creative with the shape.)
b) Measure the lengths of the interior angles, and record them in the table below.
Polygon 1
Polygon 2
Polygon 3
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Foundations 20 – Sums of Angles
c) Find the sum of the 5 interior angles.
Polygon 1:
Polygon 2:
Polygon 3:
d) What do you notice?
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Foundations 20 – Sums of Angles
Name: _______________________________
Date: ________________________________
Sums of Angles
1. a) What is the sum of the angles within a triangle?
b) Is it the same for every for any three sided polygon? (Circle one)
Yes
No
2. a) What is the sum of the angles within a four sided polygon?
b) Is it the same for any four sided polygon? (Circle one)
Yes
No
3. a) What is the sum of the angles within a five sided polygon?
b) Is it the same for any five sided polygon? (Circle one)
Yes
No
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Foundations 20 – Sums of Angles
4. Is there a pattern between the number of sides of a figure and the sum of the interior angles?
If so, what is it? If not, why do you think a pattern does not exist?
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