Geometry 1st Semester Always Sometimes Never

The triangle midline creates a triangle half the size of the original triangle.

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2 coplanar lines that never intersect are parallel.

always

2 isosceles right triangles are similar.

always

2 isosceles triangles are similar if their base angles are congruent.

always

2 non-adjacent angles created by 2 intersecting lines are congruent.

always

2 planes that intersect do so at exactly 1 line.

always

2 triangles are congruent if 2 sides and the included angle of 1 are congruent to 2 sides and the included angle of the other.

always

2 triangles are congruent if 2 sides and the included angle of one are congruent to 2 sides and the included side angle of another.

always

2 triangles are similar if 2 angles of one triangle have the measures of 50 and 70 and 2 angles of the other triangle have the measures 60 and 50.

always

2 triangles are similar if 2 angles of one triangle have the same measure of 40 and 80 and 2 angles of the other triangle have measures of 60 and 80.

always

A median of a triangle bisects the opposite side.

always

A square is a rectangle.

always

A square is a rhombus.

always

An obtuse triangle has exactly 1 obtuse angle.

always

If 10x=4y then the ratio of x to y is 2:5.

always

If 2 angles are complementary they are each acute.

always

If 2 lines are cut by a transversal so alternate interior angles are congruent the lines are parallel.

always

If 2 parallel lines are cut by a transversal the corresponding angles are congruent.

always

If 2 points of a line lie on a plane then the entire line lies in the plane.

always

If 2 points of a line lie on a plane, then the entire line lies in the plane.

always

If 2 sides of a right triangle are congruent to the corresponding parts of another right triangle the triangles are congruent.

always

If a median of a triangle is also an altitude then it is an angle bisector too.

always

If an acute angle of one right triangle is congruent to an acute angle of another right triangle the triangles are similar.

always

If the corresponding sides of 2 similar triangles are in a ratio of 3:4 then the there perimeters are in a ratio of 3:4.

always

If the perimeters of 2 similar triangles are in a ratio 2:3 then the corresponding altitudes of those triangles are in a ratio 2:3.

always

Intersecting lines are coplanar.

always

Opposite sides of a rectangle are parallel.

always

The altitude to the base of an isosceles triangle is also an angle bisector.

always

The altitude to the base of an isosceles triangle is also the median to the base.

always

The bisectors of vertical angles are opposite rays.

always

The diagonals of a rectangle bisect each other.

always

The measure of an exterior angle of a triangle is equal to the sum of the measures of the remote interior angles.

always

The measure of an exterior angle of a triangle is larger than the measure of either remote interior angles.

always

The nonparallel sides of an isosceles trapezoid are congruent.

always

The opposite angles of a rhombus are congruent.

always

The opposite angles of a square are congruent.

always

The sum of the interior angles of a convex n-gon is 360˚ greater than the sum of the angles on an (n-2) gon.

always

The supplement of an acute angle is obtuse.

always

This is your favorite class.

always

2 planes intersect in 2 parallel lines.

never

2 planes parallel to the same plane are perpendicular to each other.

never

A median of a triangle does not contain the midpoint of the side to which it is drawn.

never

A parallelogram is a trapezoid.

never

A right triangle is congruent to an obtuse triangle.

never

A right triangle is equilateral.

never

A trapezoid and a parallelogram are similar.

never

All 3 altitudes of a triangle fall outside the triangle.

never

An angle bisector of a scalene triangle divides the opposite side in a ratio of 1:1.

never

As the number of sides of a polygon increases the sum of the measures of the exterior angles increases.

never

If 2 intersecting lines are cut by a transversal the consecutive interior angles are supplementary.

never

If 2 supplementary angles are congruent their complements are 45˚.

never

If a median of a triangle is also an altitude the the triangle is scalene.

never

If a plane contains 1 of 2 skew lines it contains the other.

never

If parallel lines are cut by a transversal, then consecutive interior angles are complementary.

never

If the perimeters of 2 similar triangles are in a 1:2 ratio the the corresponding altitudes of this triangles are congruent.

never

In a plane the relation "is perpendicular to" is transitive.

never

Skew lines are coplanar.

never

The No Choice Theorem is a reason for stating 2 triangles are congruent.

never

The No Choice Thm is a reason for stating triangles are congruent.

never

The diagonals of a trapezoid bisect each other.

never

The supplement of an acute angle is acute.

never

2 isosceles obtuse triangle are similar.

sometimes

2 isosceles triangles are similar if they have at least one pair of congruent angles.

sometimes

2 lines are perpendicular to a 3rd line are skew to each other.

sometimes

2 lines that never intersect are parallel.

sometimes

2 planes parallel to parallel lines are parallel to each other.

sometimes

2 rectangles are similar.

sometimes

2 triangles are congruent if 2 sides and an angle of one are congruent to corresponding parts of another.

sometimes

A equiangular quadrilateral is regular.

sometimes

A median of a triangle bisects the angle it is drawn from.

sometimes

A parallelogram is a rhombus.

sometimes

A rhombus is a regular quadrilateral.

sometimes

A right triangle is scalene.

sometimes

A scalene triangle has 3 acute angles.

sometimes

An angle bisector of a scalene triangle divides the opposite sides in a ratio of 2:3.

sometimes

An equiangular polygon is regular.

sometimes

An isosceles triangle is obtuse.

sometimes

Consecutive sides of a parallelogram are perpendicular.

sometimes

Corresponding sides of similar triangles are congruent.

sometimes

If 2 angles are complementary and adjacent they are congruent.

sometimes

If 2 intersecting lines are cut by a transversal then the consecutive interior angles are complementary.

sometimes

If 2 lines are cut by a transversal such that 2 interior angles on the same side of the transversal are congruent the lines are parallel.

sometimes

If 2 parallel lines are cut by a transversal, then the corresponding angles are supplementary.

sometimes

If <BAC is congruent to <ABC in triangle ABC then AB is congruent to BC.

sometimes

If AB congruent to BC in triangle ABC then angle BAC congruent to angle ABC.

sometimes

If a plane contains 1 of 2 parallel lines it contains the other.

sometimes

If an angle of 1 isosceles triangle is congruent to an angle of another isosceles triangle the triangles are similar.

sometimes

If angle TAB is congruent to angle TAC then TA is perpendicular to BC.

sometimes

If parallel lines are cut by a transversal then corresponding angles are supplementary.

sometimes

If the diagonals of a quadrilateral are congruent the quadrilateral is an isosceles trapezoid.

sometimes

In an angle of one isosceles triangle is congruent to an angle of another isosceles triangle the triangles are similar.

sometimes

In space 2 lines perpendicular to a 3rd line are perpendicular to each other.

sometimes

The base of an isosceles triangle is shorter than either leg.

sometimes

The diagonals of a rectangle bisect the angles.

sometimes

The diagonals of a trapezoid are congruent.

sometimes

The leg of an isosceles triangle is shorter than the the base.

sometimes

The non parallel sides of a trapezoid are congruent.

sometimes

Vertical angles are complementary.

sometimes

Vertical angles are supplementary.

sometimes