Grade 8 Math Practice Test: Parallel Lines, Transversals and Triangle Angles
- Parallel Lines and Triangle Angles
- 10 questions
- 15 minutes
This test covers corresponding, alternate interior and same-side interior angles, the triangle angle sum and the exterior angle theorem. Tip: when two parallel lines are cut by a transversal, each angle is either equal to a given angle or adds with it to 180°.
Tap an option to mark your answer. You can change your mind, or tap the same option again to leave the question blank. The correct answers and explanations appear when you finish the test.Tap an option to answer; tap it again to leave the question blank.
Your result
- 0 correct
- 0 wrong
- 0 blank
-
Question 1
Two parallel lines are cut by a transversal. One angle measures 115°. What is the measure of the angle that corresponds to it at the other parallel line?
Correct answer: A
Corresponding angles formed by parallel lines are equal, so it is 115°. 65° is the supplement, which belongs to an angle next to it on a straight line.
-
Question 2
Two parallel lines are cut by a transversal. One of two same-side interior angles measures 72°. What is the measure of the other one?
Correct answer: A
Same-side interior angles between parallel lines are supplementary: 180° − 72° = 108°. 72° would be correct for alternate interior angles, which are equal.
-
Question 3
Two parallel lines are cut by a transversal. A pair of alternate interior angles measure (3x + 10)° and (5x − 30)°. What is x?
Correct answer: B
Alternate interior angles are equal: 3x + 10 = 5x − 30, so 40 = 2x and x = 20. 25 comes from setting the sum equal to 180°, and 70 is the angle measure, not x.
-
Question 4
Two angles of a triangle measure 47° and 68°. What is the third angle?
Correct answer: D
The angles of a triangle add to 180°: 180 − 47 − 68 = 65°. 115° is the sum of the two given angles.
-
Question 5
The two remote interior angles of a triangle measure 40° and 75°. What is the exterior angle at the third vertex?
Correct answer: B
An exterior angle equals the sum of the two remote interior angles: 40° + 75° = 115°. 65° is the interior angle at that vertex.
-
Question 6
The angles of a triangle measure x°, 2x° and 3x°. What is the largest angle?
Correct answer: B
x + 2x + 3x = 6x = 180, so x = 30 and the largest angle is 3 · 30 = 90°. 30° is the value of x, the smallest angle.
-
Question 7
The vertex angle of an isosceles triangle measures 40°. What is the measure of each base angle?
Correct answer: A
The two base angles are equal and share 180° − 40° = 140°, so each is 70°. 140° is the sum of both base angles.
-
Question 8
Triangle P has angles of 50° and 60°. Triangle Q has angles of 60° and 70°. Are the triangles similar?
Correct answer: C
The third angle of P is 70° and the third angle of Q is 50°, so all three angles match and the triangles are similar by angle-angle. Similar triangles can have different side lengths.
-
Question 9
In triangle ABC, the exterior angle at C measures 130° and angle A measures 55°. What is the measure of angle B?
Correct answer: C
The exterior angle at C equals angle A + angle B, so angle B = 130° − 55° = 75°. 50° is the interior angle at C.
-
Question 10
Two parallel lines are cut by a transversal. Two same-side interior angles measure (2x)° and (x + 30)°. What is x?
Correct answer: D
Same-side interior angles add to 180°: 2x + x + 30 = 180, so 3x = 150 and x = 50. 30 comes from setting the angles equal, which only works for alternate or corresponding angles.
Questions you leave blank are not counted as wrong.
More Math tests
MathGrade 8 Math Practice Test: Pythagorean Theorem Word Problems and DistancePythagorean Theorem Applications10 questions15 min MathGrade 8 Math Practice Test: Linear Equations and FunctionsLinear Equations and Functions12 questions15 minMathGrade 8 Math Practice Test: Exponents, Roots and the Pythagorean TheoremExponents, Roots and the Pythagorean Theorem12 questions15 minMathGrade 8 Math Practice Test: Systems of Linear EquationsSystems of Linear Equations12 questions15 minMathGrade 8 Math Practice Test: Transformations and Volume of Cylinders, Cones and SpheresTransformations and Volume15 questions20 minMathGrade 8 Math Practice Test: Scientific NotationScientific Notation10 questions15 minMathGrade 8 Math Practice Test: Rational and Irrational NumbersRational and Irrational Numbers10 questions15 min