Geometryvocabulary

Line segmentA part of a line.

It has 2 endpoints.

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lineA straight path that goes on forever in both directions.

It has no beginning.

It has no end.

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rayPart of a line

It has an endpoint (starting point)

It goes on in one direction forever.

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angle2 rays with a common endpoint

There are 3 types of anglesRight angles: have a square corner

Acute angle: is smaller than a right angle

Obtuse angle: is larger than a right angle

Plane FiguresAre flat figures (shapes)

They can be open

Or closed

PolygonPoly=many

Is a closed plane figure that has 3 or more sides.

The sides are line segmentsTriangle (3 sides)

Square (4 sides)

Pentagon (5 sides)

QuadrilateralA polygon with 4 sides and 4 angles

Parallelogram A quadrilateral with 2 sets of parallel sides

Rectangle A quadrilateral with 2 sets of parallel sides AND 4 right angles

Square4 equal sides

4 right angles

2 sets of parallel sides

rhombus4 equal sides

Trapezoid A quadrilateral with 1 set of parallel sides

ParallelParallel are always the same distance apart.

If you extended forever, they’d never touch each other

TriangleA polygon with 3 sides and 3 angles (corners)

Equilateral Triangle

All 3 sides are equal length

All three angles are the same size

Isosceles Triangle2 sides are equal in length

2 angles are equal

Right TriangleOne angle is equal to 90 degrees

90 degrees = a right angle

Congruent Shapes that are the same size and shape.

They may be flipped or turned.

Not congruent May be a similar shape or size, but not the same.