Download Triangle Construction

Triangle Construction
Common Core Standard: Draw (freehand, with ruler and protractor, and with technology) geometric shapes with given
conditions. Focus on constructing triangles from three measures of angles or sides, noticing when the conditions determine
a unique triangle, more than one triangle, or no triangle.
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There are multiple types of triangles, these can be determined by using the angles in the triangle and the lengths of
the sides of triangle
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Types of Triangles:
o
By side lengths:

Scalene Triangle- is a triangle in which all sides measure a different length

Isosceles Triangle- is a triangle in which 2 sides measures the same length
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Equilateral Triangle- is a triangle in which all sides are equal
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Note: Equilateral Triangles are also equal angular triangles, this means that all angles in an
equilateral triangle are equal (in fact they all measure 60o)
o
By angle measurement:
o
Note: The angles inside a triangle always have a sum of 180o

Right triangle – has one right angle (it is impossible to have more than 1 right angle in a triangle)
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Obtuse triangle – has one obtuse angle (it is impossible to have more than 1 obtuse angle in a
triangle)
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Acute triangle- all three angles are acute
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This means that all equilateral triangles are also acute triangles

Note: that in both a right triangle and an obtuse triangle the other two angles in both
triangles are acute
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Example: Determine which types of triangles are shown below:
o
The yellow triangle is a scalene obtuse triangle, because the sides all measure different lengths and obtuse,
because one angle is greater than 90o
o
The middle triangle is an equilateral acute triangle
o
The last triangle is acute isosceles, because all the angles are less than 90o and two of the sides are equal