Post on 12-Jan-2016
transcript
2.7 – Triangles
Type of ∆ Definition Picture
Equilateral Triangle
CL
AS
SIF
ICA
TIO
N B
Y S
IDE
S
All sides are ≅
Type of ∆ Definition Picture
Isosceles Triangle
CL
AS
SIF
ICA
TIO
N B
Y S
IDE
S
2 Sides ≅
base
leg leg
Type of ∆ Definition Picture
Scalene Triangle
CL
AS
SIF
ICA
TIO
N B
Y S
IDE
S
No sides are ≅
Type of ∆ Definition Picture
EquiangularTriangle
CL
AS
SIF
ICA
TIO
N B
Y A
NG
LE
S
All angles are ≅
Type of ∆ Definition Picture
Acute Triangle
CL
AS
SIF
ICA
TIO
N B
Y A
NG
LE
S
All angles are acute
Type of ∆ Definition Picture
Right Triangle
CL
AS
SIF
ICA
TIO
N B
Y A
NG
LE
S
One right angle
leg
leghyp
oten
use
Type of ∆ Definition Picture
Obtuse Triangle
CL
AS
SIF
ICA
TIO
N B
Y A
NG
LE
S
One obtuse angle and 2 acute angles
Classify the triangle by the best definition based on sides and angles. Then find the sum of the interior angles.
scalene
right
180
equilateral
equiangular
180
isosceles
obtuse
180
4. The sum of ANY triangles interior angles is 180°. Use this fact to solve for x below.
x + 75 + 54 = 180
x + 129 = 180
x = 51
2x + 3x + 55 = 180
5x + 55 = 180
x = 25
5x = 125
4x – 1 + 3x + 90 = 180
7x + 89 = 180
x = 13
7x = 91
A = 30 un2
A = ½(12)(5)
A = 30 un2
A = ½(12)(5)
A = 30 un2
A = ½(12)(5)
b
h
b
h
Triangle:
Picture Perimeter Area
Triangle
Add the 3 sides
2
bhA
1
2A bh
30 16 34P 80P in
130 16
2A
2240A in
1
2A bh
20 48 39P 107P cm
148 15
2A
2360A cm
1
2A bh
7 13 10P 30P m
110 5
2A
225A m
1
2A bh
4. If the area of the triangle is 63cm2, find the height of the triangle.
1
2A bh
163 21
2h
126 21h6cm h