Interior Angles
Triangles
Can You Build It?
Ordering Angles
100
The sum of the interior angles of a triangle is...
180
100
Find the missing interior angle.
26 degrees
100
Which of the following sets of side lengths can form a triangle?
a) 12, 19, 7.001
b) 3, 7, 9
c) 18, 24, 5
d) 72, 19, 91.1
a and b both form triangles. c and d do not.
100
Is it a triangle?
8, 18, 24
Yes!
8+18>24
200
The formula for the sum of the interior angles of a polygon with n sides is...
180(n-2), or 180n - 360
200
Find the measure of angle 2
72 degrees
200
A triangle has side lengths of 3 and 4. The range of values of the third side can be expressed by this inequality, written in the form,
(lower bound) < x < (upper bound)
1 < x < 7
200
Is it a triangle?
28, 50, 90
No!
28+50>90
300
The interior angle sum of a 9-sided polygon, also called a nonagon or enneagon, is this number of degrees.
1260°
300
Find x.
x = 4
300
A triangle has side lengths of 12.9 and 18.6. The range of values of the third side can be expressed by this inequality, written in the form,
(lower bound) < x < (upper bound)
5.7 < x < 31.5
300
Is it a triangle?
41, 7, 55
No!
7+41<55
400
The sum of the interior angles of a polygon with 17 sides is...
2700
400
Triangle ABC has angle A = (12x-4)°, and angle B = (18x+10)°. The exterior angle at C = (24x+18)°.
Find x.
x = 2
400
A triangle has side lengths of 5 and 13. The range of values of the third side can be expressed by this inequality, written in the form,
(lower bound) < x < (upper bound)
8 < x < 18
400
33°, 38°, 114°
33+38+144 = 185
(It is not equal to 180)
500
The sum of the interior angles of a polygon with 1000 sides is...
179640 degrees
500
Find x.
x = 67
500
A triangle has side lengths of a and b. The range of values of the third side can be expressed by this inequality, written in the form,
(lower bound) < x < (upper bound)
|a-b| < x < a+b
500
34°, 34°, 112°
Yes!
34 + 34 + 112 = 180
(It is equal to 180)