Angles, Parallel Lines and Triangles: Grade 8 Math Quiz – PDF Download
Ten multiple-choice questions check triangle angle sums, exterior angles, angles formed by a transversal and the AA criterion. Each question has exactly one correct answer. Read the explanation to learn the typical mistake.
Grade 8Common Core: 8.G.A.5
🎯 Angles, Parallel Lines and Triangles – Grade 8 math quiz
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Question 1
Two angles of a triangle measure \(38^{\circ}\) and \(74^{\circ}\). What is the third angle?
A\(112^{\circ}\)
B\(142^{\circ}\)
C\(78^{\circ}\)
D\(68^{\circ}\)
Question 2
The remote interior angles of a triangle measure \(47^{\circ}\) and \(62^{\circ}\). What is the exterior angle?
A\(71^{\circ}\)
B\(109^{\circ}\)
C\(133^{\circ}\)
D\(118^{\circ}\)
Question 3
Lines \(l\) and \(m\) are parallel. What is the measure of the angle marked \(?\)
Lines \(l\) and \(m\) are parallel.
A\(55^{\circ}\)
B\(65^{\circ}\)
C\(235^{\circ}\)
D\(125^{\circ}\)
Question 4
Two parallel lines are cut by a transversal. Same-side interior angles measure \((2x+10)^{\circ}\) and \((3x+20)^{\circ}\). What is \(x\)?
A\(x=30\)
B\(x=36\)
C\(x=20\)
D\(x=60\)
Question 5
Two parallel lines are cut by a transversal. Which pair of angles is always equal?
ACorresponding angles
BSame-side interior angles
CAngles that form a linear pair
DAngles that are next to each other along the transversal
Question 6
What is the measure of the exterior angle \(x\)?
Triangle \(ABC\).
A\(70^{\circ}\)
B\(130^{\circ}\)
C\(120^{\circ}\)
D\(110^{\circ}\)
Question 7
Which pair of triangles must be similar?
AOne has angles \(40^{\circ}\) and \(80^{\circ}\); the other has angles \(40^{\circ}\) and \(70^{\circ}\)
BOne has angles \(50^{\circ}\) and \(60^{\circ}\); the other has angles \(70^{\circ}\) and \(60^{\circ}\)
COne has angles \(50^{\circ}\) and \(60^{\circ}\); the other has angles \(60^{\circ}\) and \(80^{\circ}\)
DOne has angles \(30^{\circ}\) and \(90^{\circ}\); the other has angles \(60^{\circ}\) and \(60^{\circ}\)
Question 8
The triangles are similar. \(AB=6\), \(BC=8\) and \(DE=9\). What is \(EF\)?
Triangles \(ABC\) and \(DEF\).
A\(11\)
B\(\frac{16}{3}\)
C\(12\)
D\(18\)
Question 9
The angles of a triangle are in the ratio \(2:3:4\). What is the largest angle?
A\(60^{\circ}\)
B\(90^{\circ}\)
C\(80^{\circ}\)
D\(72^{\circ}\)
Question 10
Two parallel lines are cut by a transversal, and one of the eight angles measures \(70^{\circ}\). How many of the eight angles measure \(70^{\circ}\)?
A4
B2
C6
D8
🎉 Quiz complete!
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Remember:
Standard 8.G.A.5: angle sum, exterior angles, parallel lines with a transversal, and the AA criterion.
Triangle angle sum: \(180^{\circ}\).
Exterior angle = sum of the two remote interior angles.
Parallel lines: corresponding, alternate interior and alternate exterior angles are equal; same-side interior angles sum to \(180^{\circ}\).
AA criterion: two equal pairs of angles make triangles similar.
