Download Classwork/Homework Classifying Triangles

Classwork/Homework
Classifying Triangles
Matching triangles. Match the triangle description with the most specific
name.
1. Side lengths: 2cm, 3cm, 4cm B
2. Side lengths: 3cm, 2cm, 3cm E
3. Side lengths: 4cm, 4cm, 4cm A
4. Angle measures: 60°, 60°, 60° D
5. Angle measures 30°, 60°, 90° F
6. Angle measures 20°, 145°, 15° C
A.
B.
C.
D.
E.
F.
Classify the triangle by its angles and its sides.
7.
8. E
B
59°
59°
A
Equilateral
Scalene
Obtuse
Equiangular
Isosceles
Right
9.
L
62°
acute isosceles
M
120°
N
F
D
C
right isosceles
obtuse scalene
10
11.
J
T
85°
L
45°
12.
Q
U
42°
42°
50°
P
K
R
V
acute scalene
obtuse isosceles
right scalene
Logical Reasoning: Complete the statement using always, sometimes, or
never.
13. An isosceles triangle is sometimes an equilateral triangle.
14. An obtuse triangle is sometimes an isosceles triangle.
15. A triangle never has a right angle and an obtuse angle.
Quadrilateral
Both pairs of Opposite sides parallel
Parallelogram
90° angles
Trapezoid
4 congruent sides
Rectangle
Rhombus
4 congruent sides
Square
exactly 1 pair of opposite sides parallel
90° angles
legs are congruent
Isosceles
Trapezoid
Graph quadrilateral ABCD using each set of given points. Determine if
quadrilateral ABCD can be best described as a trapezoid, a square, a rectangle,
or a rhombus. SHOW ALL WORK.
1. A(−4, −2), B(2, 4), C(8, −2), D(2, −8)
Square
Slopes are negative reciprocals ⊥ lines
AB: m = 1 BC: m = -1 CD: m = 1 DA: m = -1
B•
4 sides are congruent
AB = 72
BC = 72
•C
A•
CD = 72
DA = 72
•D
2. A(0, 6), B(3, 4), C(−1, −2), D(−4, 0)
Rectangle
A•
B•
•D
•C
Slopes are negative reciprocals ⊥ lines
2
AB : m = −
3
3
BC : m =
2
2
CD : m = −
3
3
DA : m =
2
5. A(1, 0), B(2, 4), C(10, 2), D(5, 1)
QUADRILATERAL – note, slopes for AD
and DC are different, therefore it is not a
straight line.
B•
A•
•D
•C
6. A(−5, 3), B(0, 6), C(5, 3), D(0, 0)
RHOMBUS Four congruent sides
AB = 72
BC = 72
B•
A•
•C
•D
CD = 72
DA = 72