Class 7 Maths Chapter 6 MCQ: Chapter 6 of Class 7 Maths, Triangles and Its Properties, is an important part of the CBSE syllabus that introduces students to the world of angles, sides, and triangle rules like the Pythagoras Theorem, angle sum property, and types of triangles.
Practicing Maths MCQ questions for Class 7 helps strengthen conceptual understanding and boosts problem-solving speed. These Class 7 Maths MCQs are specially designed to test your knowledge in a quick and effective way, making them perfect for last-minute revision.
You can also download the MCQ questions for Class 7 Maths with answers PDF for offline practice and self-assessment. Whether you’re preparing for a class test or just brushing up your concepts, these Class 7 Maths Chapter 6 MCQ are a smart way to review and score better.
MCQ for Class 7 Maths Chapter 6 Triangle and its Properties
Here are 35 Class 7 Maths Chapter 6 MCQ on Triangle and its Properties. Each question includes an answer and a short explanation.
Question 1: Which of the following is NOT a valid criterion for determining if a triangle can be constructed?
(a) SSS
(b) SAS
(c) ASA
(d) ASS
Answer: (d) ASS
Explanation: SSS (Side-Side-Side), SAS (Side-Angle-Side), and ASA (Angle-Side-Angle) are valid criteria for triangle construction. ASS (Angle-Side-Side) is not a valid criterion.
Question 2: The sum of the interior angles of a triangle is always:
(a) 90°
(b) 180°
(c) 270°
(d) 360°
Answer: (b) 180°
Explanation: The Angle Sum Property of a triangle states that the sum of its interior angles is always 180 degrees.
Question 3: In a triangle, if two angles are 60° and 80°, the third angle is:
(a) 20°
(b) 30°
(c) 40°
(d) 50°
Answer: (c) 40°
Explanation: 180° – (60° + 80°) = 180° – 140° = 40°
Also Check: NCERT Solutions for Class 7 Maths
Question 4: A triangle with sides of different lengths is called:
(a) Equilateral
(b) Isosceles
(c) Scalene
(d) Acute
Answer: (c) Scalene
Explanation: A scalene triangle has all three sides of different lengths.
Question 5: A triangle with two sides of equal length is called:
(a) Equilateral
(b) Isosceles
(c) Scalene
(d) Right-angled
Answer: (b) Isosceles
Explanation: An isosceles triangle has two sides of equal length.
Question 6: A triangle with all three sides of equal length is called:
(a) Equilateral
(b) Isosceles
(c) Scalene
(d) Obtuse
Answer: (a) Equilateral
Explanation: An equilateral triangle has all three sides of equal length.
Question 7: Each angle of an equilateral triangle measures:
(a) 30°
(b) 60°
(c) 90°
(d) 120°
Answer: (b) 60°
Explanation: In an equilateral triangle, all angles are equal, and their sum is 180°. Therefore, each angle is 180°/3 = 60°.
Also Check: Class 7 Maths Chapter 6 Worksheet
Question 8: A triangle with one angle greater than 90° is called:
(a) Acute
(b) Right
(c) Obtuse
(d) Equilateral
Answer: (c) Obtuse
Explanation: An obtuse triangle has one angle greater than 90 degrees.
Question 9: A triangle with one angle equal to 90° is called:
(a) Acute
(b) Right
(c) Obtuse
(d) Isosceles
Answer: (b) Right
Explanation: A right triangle has one angle equal to 90 degrees.
Question 10: A triangle with all angles less than 90° is called:
(a) Acute
(b) Right
(c) Obtuse
(d) Scalene
Answer: (a) Acute
Explanation: An acute triangle has all angles less than 90 degrees.
Question 11: The side opposite the right angle in a right-angled triangle is called:
(a) Base
(b) Perpendicular
(c) Hypotenuse
(d) Altitude
Answer: (c) Hypotenuse
Explanation: The hypotenuse is the longest side in a right-angled triangle and is opposite to the right angle.
Also Check: NCERT Solutions for Class 6 Maths Chapter 6
Question 12: In a right-angled triangle, if one acute angle is 30°, the other acute angle is:
(a) 45°
(b) 60°
(c) 90°
(d) 120°
Answer: (b) 60°
Explanation: The sum of the two acute angles in a right-angled triangle is 90°. So, 90° – 30° = 60°.
Question 13: The perpendicular line segment from a vertex of a triangle to its opposite side is called:
(a) Median
(b) Altitude
(c) Angle bisector
(d) Side bisector
Answer: (b) Altitude
Explanation: An altitude is a line segment from a vertex of a triangle perpendicular to the opposite side (or the extension of that side).
Question 14: The line segment joining a vertex of a triangle to the midpoint of its opposite side is called:
(a) Median
(b) Altitude
(c) Angle bisector
(d) Perpendicular bisector
Answer: (a) Median
Explanation: A median is a line segment from a vertex of a triangle to the midpoint of the opposite side.
Question 15: If the three angles of a triangle are in the ratio 1:2:3, the triangle is a:
(a) Acute triangle
(b) Obtuse triangle
(c) Right triangle
(d) Equilateral triangle
Answer: (c) Right triangle
Explanation: Let the angles be x, 2x, and 3x. x + 2x + 3x = 180°, so 6x = 180°, x = 30°. The angles are 30°, 60°, and 90°.
Also Check: Class 6 Maths Chapter 6 Extra Questions
Question 16: An exterior angle of a triangle is equal to the sum of:
(a) All interior angles
(b) Its adjacent interior angle
(c) The two opposite interior angles
(d) All exterior angles
Answer: (c) The two opposite interior angles
Explanation: This is the Exterior Angle Property of a triangle.
Question 17: If an exterior angle of a triangle is 100° and one of the interior opposite angles is 60°, the other interior opposite angle is:
(a) 40°
(b) 60°
(c) 80°
(d) 160°
Answer: (a) 40°
Explanation: 100° – 60° = 40°
Question 18: Which of the following sets of side lengths can form a triangle?
(a) 2 cm, 3 cm, 6 cm
(b) 3 cm, 4 cm, 5 cm
(c) 1 cm, 2 cm, 3 cm
(d) 4 cm, 5 cm, 10 cm
Answer: (b) 3 cm, 4 cm, 5 cm
Explanation: The sum of any two sides of a triangle must be greater than the third side. Only (b) satisfies this condition (3+4>5, 4+5>3, 3+5>4).
Question 19: In triangle ABC, if AB = 5 cm, BC = 7 cm, and AC = 8 cm, which is the longest side?
(a) AB
(b) BC
(c) AC
(d) Cannot be determined
Answer: (c) AC
Explanation: AC (8 cm) is the longest side.
Question 20: In triangle PQR, if angle P = 70° and angle Q = 30°, then the exterior angle at R is:
(a) 70°
(b) 30°
(c) 100°
(d) 80°
Answer: (c) 100°
Explanation: The exterior angle at R is equal to the sum of angles P and Q: 70° + 30° = 100°.
Question 21: A triangle can have at most how many right angles?
(a) 0
(b) 1
(c) 2
(d) 3
Answer: (b) 1
Explanation: A triangle can have at most one right angle. If it had two, the sum of the angles would exceed 180 degrees.
Question 22: A triangle can have at most how many obtuse angles?
(a) 0
(b) 1
(c) 2
(d) 3
Answer: (b) 1
Explanation: Similar to right angles, a triangle can have at most one obtuse angle.
Also Check: RD Sharma Solutions Class 7 Maths Properties of Triangles
Question 23: The sum of the lengths of any two sides of a triangle is ______ the length of the third side.
(a) Equal to
(b) Less than
(c) Greater than
(d) Half of
Answer: (c) Greater than
Explanation: This is a fundamental property of triangles known as the Triangle Inequality Theorem.
Question 24: If two angles of a triangle are 45° and 45°, the triangle is:
(a) Scalene
(b) Isosceles
(c) Equilateral
(d) Obtuse
Answer: (b) Isosceles
Explanation: Since two angles are equal, the sides opposite to them are also equal, making it an isosceles triangle.
Question 25: If one angle of a triangle is 120°, it is a/an:
(a) Acute triangle
(b) Right triangle
(c) Obtuse triangle
(d) Equilateral triangle
Answer: (c) Obtuse triangle
Explanation: An obtuse triangle has one angle greater than 90°.
Question 26: In a triangle, the angle opposite the longest side is the:
(a) Smallest angle
(b) Right angle
(c) Largest angle
(d) Cannot be determined
Answer: (c) Largest angle
Explanation: The side opposite the largest angle is always the longest side, and vice-versa.
Question 27: The point of intersection of the medians of a triangle is called the:
(a) Circumcenter
(b) Incenter
(c) Centroid
(d) Orthocenter
Answer: (c) Centroid
Explanation: The centroid is the point where the three medians of a triangle intersect.
Question 28: The point of intersection of the altitudes of a triangle is called the:
(a) Circumcenter
(b) Incenter
(c) Centroid
(d) Orthocenter
Answer: (d) Orthocenter
Explanation: The orthocenter is the point where the three altitudes of a triangle intersect.
Question 29: The angle bisector of a triangle divides the angle into two ______ angles.
(a) unequal
(b) acute
(c) equal
(d) obtuse
Answer: (c) equal
Explanation: An angle bisector divides an angle into two equal angles.
Question 30: If the perimeter of an equilateral triangle is 24 cm, then the length of each side is:
(a) 6 cm
(b) 8 cm
(c) 12 cm
(d) 24 cm
Answer: (b) 8 cm
Explanation: In an equilateral triangle, all sides are equal. Perimeter = 3 * side. So, side = 24 cm / 3 = 8 cm.
Question 31: Which triangle has no line of symmetry?
(a) Equilateral triangle
(b) Isosceles triangle
(c) Scalene triangle
(d) Right-angled isosceles triangle
Answer: (c) Scalene triangle
Explanation: A scalene triangle has no sides equal, and therefore no line of symmetry.
Question 32: In an isosceles triangle, the angles opposite to the equal sides are:
(a) Equal
(b) Unequal
(c) Right
(d) Obtuse
Answer: (a) Equal
Explanation: This is a property of isosceles triangles: angles opposite equal sides are equal.
Question 33: The sum of the interior angles of a quadrilateral is:
(a) 90°
(b) 180°
(c) 270°
(d) 360°
Answer: (d) 360°
Explanation: While this question is about a quadrilateral, it’s related to understanding angles in polygons, and can sometimes be linked to triangle properties (since quadrilaterals can be divided into two triangles).
Question 34: How many altitudes can a triangle have?
(a) 1
(b) 2
(c) 3
(d) Infinite
Answer: (c) 3
Explanation: A triangle has three vertices, and you can draw one altitude from each vertex to the opposite side.
Question 35: If in a △ABC, ∠A+∠B=90
o , then the triangle is a:
(a) Acute angled triangle
(b) Obtuse angled triangle
(c) Right angled triangle
(d) Equilateral triangle
Answer: (c) Right angled triangle
Explanation: If the sum of two angles is 90°, the third angle must be $180^o – 90^o = 90^o$. A triangle with a 90° angle is a right-angled triangle.
