Download Acute Triangle Equiangular Triangle Right Triangle Obtuse

Acute
Triangle
Equiangular
Triangle
Right
Triangle
Obtuse
Triangle
Equilateral
Triangle
Isosceles
Triangle
Scalene
Triangle
Question: What is
this side of a right
triangle called?
A triangle with 3
congruent angles
A triangle with all 3 angles
less than 90°
A triangle with an
angle greater than 90°
A triangle with a
90°angle
A triangle with at
least 2 congruent sides
A triangle with all
sides congruent
Hypotenuse
A triangle with no equal
sides (each side has a
different length)
(side opposite the
right angle)
Question: What
are these sides
called?
Exterior Angle
Theorem
Question: Can you prove
these Δ’s are congruent?
Why?
Question: Can you prove
these Δ’s are congruent?
Why?
Triangle Sum
Theorem
Question: Can you prove
these Δ’s are congruent?
Why?
Question: Can you prove
these Δ’s are congruent?
Why?
CPCTC
The interior angles of a
triangle add up to 180°
Legs
(of a right triangle)
m∠A + m∠B + m∠C = 180°
Yes, by Side-Side-Side
congruence postulate
(SSS)
An exterior angle is equal to
the sum of the other
2 interior angles
m∠1 = m∠A +m∠B
Yes, by Side-Angle-Side
congruence postulate
(SAS)
C ongruent P arts
of C ongruent T riangles
are C ongruent
Yes, by Angle-Side-Angle
congruence postulate
(ASA)
Yes, by Angle-Angle-Side
congruence postulate
(AAS)
Question: Can you prove
these Δ’s are congruent?
Why?
Question: Can you prove
these Δ’s are congruent?
Why?
Question
What theorems prove
Triangle congruence?
Question: Can you prove
these Δ’s are congruent?
Why?
Base Angles Theorem
NO, Side-Side-Angle (SSA)
does not prove
triangle congruence!
The base angles of an
isosceles triangle are
congruent
NO, Angle-Angle-Angle (AAA)
does not prove
triangle congruence!
SSS, SAS, ASA, AAS,
HL
Yes, by Hypotenuse-Leg
congruence theorem
(HL)