Lines and Points
A figure that begins at an endpoint and goes on forever the other way
What is a ray
An angle that measures more than 90 degrees
What is an obtuse angle
Which set of angle measures could be the interior angles of a triangle?
A. 25°, 30°, 35°
B. 35°, 60°, 75°
C. 45°, 60°, 75°
D. 60°, 90°, 120°
C. 45°, 60°, 75°
Angles must add up to 180
Which set of side lengths could be used to create a triangle?
A. 1 ft, 2 ft, 3 ft
B. 5 ft, 9 ft, 13 ft
C. 8 ft, 12 ft, 20 ft
5 ft, 9 ft, 13 ft
Remember that the sum of 2 sides must
be greater than the third side.
A triangle that has one 90 degree angle
What is a right triangle
Two angles that add up to 180°.
Supplementary angles add up to 180
This type of angle measures 180 degrees
What is a straight angle
Which three angle measures would not be possible in a triangle?
A. 25°, 50°, 105
B. 40°, 65°, 75°
C. 45°, 45°, 90°
D. 50°, 65°, 80°
D. 50°, 65°, 80°
Angles must add to 180.
One side of a triangle measures 4 cm. Which can be the measures of the other two sides of the triangle?
A. 5 cm and 9 cm
B. 6 cm and 9 cm
C. 6 cm and 10 cm
D. 7 cm and 12 cm
B. 6 cm and 9 cm
....because 6 + 4 > 9
This triangle has two acute angles and one obtuse angle
What is an obtuse triangle
Something that parallel lines will never do
What is intersect
The point where two angles meet
What is the vertex
Mark drew an isosceles triangle. Two sides of his triangle measure 3 inches and 7 inches. What is the measure of the third side of Mark’s triangle?
A. 3 inches
B. 5 inches
C. 7 inches
D. 9 inches
C. 7 inches
2 sides must be equal. the shorter sides must add up longer than the third side
An isosceles triangle has an angle that measures 100°. What is the measure of one of the other angles in the isosceles triangle?
A. 40°
B. 60°
C. 80°
D. 100°
A. 40°
There are 180° in a triangle.
180 - 100 = 80
If one angle is 100, the other 2 angles add up to 80.
A triangle with three equal sides can be classified in these two ways
What are equilateral triangle and isosceles triangle
Part of a line with 2 endpoints
What is a segment
The measure of two adjacent angles are 63 degrees and 27 degrees. Use one word to describe the sum of the angles.
What is complimentary
An isosceles triangle has an angle that measures 68°. What is the measure of one of the other angles in the isosceles triangle?
A. 22°
B. 56°
C. 60°
D. 112°
180 - 68 = 112
Two angles of an isosceles triangle are equal. half of 112 is 56
One side of a triangle measures 14 cm. Another side of the same triangle measures 6 cm. Which inequalities represent all possible lengths of the third side, x?
A. x > 6 and x < 14
B. x ≥ 6 and x ≤ 14
C. x > 8 and x <20
D. x ≥ 8 and x ≤20
C. x > 8 and x <20
Remember that the two shorter sides must be longer than the longest side.
The third angle of a triangle with one 25 degree angle, and one 69 degree angle
What is 86 degrees
If two lines create a set of vertical angles, they must be these type of lines
What are intersecting lines
Angle 1 and 3 are vertical. Angle 1 and 2 are adjacent and supplementary. If angle 2 is 35 degrees, this is the measure of angle 3.
What is 145 degrees
A triangle has angles that measure 42° and 48°. One side of the triangle measures 5 inches. Which terms describe the triangle?
A. acute, isosceles
B. right, isosceles
C. acute, scalene
D. right, scalene
Angles are 42°, 48°, and 90° since all angles have to add to 180°.
D. right, scalene
Which could be the side lengths of an isosceles triangle?
A. 2 inches, 2 inches, and 5 inches
B. 2 inches, 3 inches, and 4 inches
C. 2 inches, 3 inches, and 3 inches
D. 3 inches, 3 inches, and 6 inches
C. 2 inches, 3 inches, and 3 inches
The two shorter sides must add to be longer than the third side. An isosceles triangle has 2 sides equal.
If all angles of a triangle are congruent, this is the measure that each angle will have.
What is 60 degrees