Angle and Triangle
Flash Cards
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Angle
A
B
C
Two rays with a
common endpoint
called a vertex.
Always name an angle with
the vertex in the middle.
Adjacent Angles
Angles that share a
vertex and a side.
Congruent Angles
X
64°
64°
Y
Angles with the same
measure.
Vertical Angles
Angles formed by
intersecting lines and
are opposite each other.
Vertical angles are always
congruent!
Acute Angles
The measure of the
angle is less than 90°.
Obtuse Angles
The measure of the
angle is greater
than 90° and less than
180°.
Right Angles
The measure of the
angle is 90°.
Complementary
Angles
The sum of the two
angles is 90°.
Supplementary
Angles
The sum of the two
angles is 180°.
SCALENE TRIANGLE
All three sides have different
lengths:
ISOSCELES TRIANGLE
Has at least 2 congruent sides
EQUILATERAL TRIANGLE
All three sides are congruent
ACUTE TRIANGLE
All of the angles are acute
(less than 90°)
OBTUSE TRIANGLE
One obtuse angle
(greater than 90 less than 180)
RIGHT TRIANGLE
Has one right angle (90°)