Introduction to Triangles Congruence

Find the measure of the indicated angle. 

• 26

• 36

• 85

• 144

Tags

CCSS.8.G.A.5

Find the perimeter of this triangle.

• 12 in

• 22 in

• 18 in

• 24 in

Tags

CCSS.3.MD.D.8

• Reflexive property of congruence

• Same-side interior angles theorem

• Base angles theorem

• Triangle sum theorem (TST)

Tags

CCSS.HSG.SRT.B.5

The measure of an exterior angle of a triangle is equal to _________________.

• The sum of the measures of the remote interior angles.

• The sum of the measures of the interior angles.

• The measure of its adjacent interior angle.

• 360

Tags

CCSS.8.G.A.5

Tags

CCSS.HSG.CO.B.7

In triangles, the size of an angle determines how long the side opposite it becomes (big angles are opposite long sides. Don't worry, we'll prove this). The converse is also true. A long side means the angle opposite must be bigger. In an isosceles triangle, we have at least two sides that are congruent. What does this tell us?

• The angles opposite those sides must be congruent.

• The angles adjacent to those sides must be congruent

• The angles exterior to those sides must be congruent

• The angles formed by those sides must be congruent.

Tags

CCSS.HSG.CO.C.9

We know that equilateral triangles are just special isosceles triangles. What does the base angles theorem tell us must be another property of an equilateral triangle?

• It's also equiangular (it has 3 congruent angles)

• It also has exactly two congruent angles.

• All of its sides are congruent.

Tags

CCSS.4.G.A.2

Proving Congruence: Instead of having to prove that all six parts (3 sides, 3 angles) of a triangle have corresponding parts in another triangle, we can use postulates to say two triangles are congruent if they have a three corresponding parts. In the diagram, how do we know that segments SM, RM, PM, and QM are congruent?

• They are radii of the same circle.

• They are marked as congruent.

• They look like they are congruent.

• M is the midpoint of segments SQ and PR.

Tags

CCSS.HSG.SRT.B.5

Tags

CCSS.HSG.CO.B.7