Download Classifying Triangles

Classifying Triangles
• By angles
– Acute- all angle measures < 90
– Obtuse- one angle measure > 90
– Right- one angle = 90
– Equiangular- all angle measures are equal
• By sides
– Scalene- no two sides are congruent
– Isosceles- at least two sides are congruent
– Equilateral- all sides are congruent
ARCHITECTURE The triangular truss below is modeled for steel
construction. Classify
JMN, JKO, and OLN as acute, equiangular, obtuse, or right.
Answer:
JMN has one angle with measure greater than 90, so it is an obtuse triangle.
JKO has one angle with measure equal to 90, so it is a right triangle.
OLN is an acute triangle with all angles congruent, so it is an equiangular
triangle.
ARCHITECTURE The frame of this window design is made up of many
triangles. Classify ABC, ACD, and ADE as acute, equiangular, obtuse, or
right.
Answer:
ABC is acute. ACD is
obtuse. ADE is right.
Identify the isosceles triangles in the figure if
Isosceles triangles have at least two sides congruent.
Answer:
UTX and UVX are isosceles.
Identify the scalene triangles in the figure if
Scalene triangles have no congruent sides.
Answer:
VYX, ZTX, VZU, YTU, VWX, ZUX, and
YXU are scalene.
Identify the indicated triangles in the figure.
a. isosceles triangles
Answer: ADE, ABE
b. scalene triangles
Answer: ABC, EBC, DEB, DCE, ADC, ABD
ALGEBRA Find d and the measure of each side of equilateral triangle KLM if
and
Since KLM is equilateral, each side has
the same length. So
Substitution
Subtract d from each side.
Add 13 to each side.
Divide each side by 3.
Next, substitute to find the length of each side.
Answer: For KLM,
and the measure of each side is 7.
ALGEBRA Find x and the measure of each side of equilateral triangle
and
Answer:
if
COORDINATE GEOMETRY Find the measures of the sides of RST. Classify
the triangle by sides.
Use the distance formula to find the lengths of each side.
Answer:
RST is scalene.
; since all 3 sides have different lengths,
Find the measures of the sides of ABC. Classify the triangle by sides.
Answer:
ABC is scalene.
; since all 3 sides have different lengths,