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

64° 64° Y X

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°)