alleryStart learning →Two angles of a triangle are 50° and 60°. What is the third angle?
- 70°
- 60°
- 80°
- 130°
Show answer and solution
Correct answer: A. 70°
The three angles add up to 180°, so the third is 180° minus 110°, which is 70°.
Olympiad (Class 7) Triangles and congruence of triangles — practice questions
Explore 57 free Triangles and congruence of triangles questions in Olympiad (Class 7) Mathematics. Open each question or exercise to read its content, reference answers and available explanation.
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Showing questions 1–30 of 57.
Two angles of a triangle are 50° and 60°. What is the third angle?Read the answer and worked solution →An exterior angle of a triangle is 125° and one far interior angle is 70°. Find the other far interior angle.Read the answer and worked solution →What is the sum of the three exterior angles of a triangle, taking one at each vertex?Read the answer and worked solution →Which set of lengths in cm can be the sides of a real triangle?Read the answer and worked solution →Two sides of a triangle are 7 cm and 10 cm. Which length can the third side be?Read the answer and worked solution →A real triangle has sides 8 cm and 3 cm and a whole-number third side. How many values are possible?Read the answer and worked solution →An isosceles triangle has two sides of lengths 4 cm and 9 cm. What is its perimeter?Read the answer and worked solution →A triangle whose three sides all have different lengths is called what?Read the answer and worked solution →A triangle has one angle of 105°. What kind of triangle is it?Read the answer and worked solution →A triangle has angles 45°, 45° and 90°. Which description fits it?Read the answer and worked solution →How large is each angle of an equilateral triangle?Read the answer and worked solution →The vertex angle of an isosceles triangle is 40°. What is each base angle?Read the answer and worked solution →An isosceles triangle has a base angle of 80°. What is its vertex angle?Read the answer and worked solution →Two triangles have two equal sides and the equal angle between them. Which rule shows congruence?Read the answer and worked solution →Which congruence rule needs only side lengths and no angle information?Read the answer and worked solution →Two angles and the side between them are equal in two triangles. Which rule applies?Read the answer and worked solution →Which condition does NOT by itself prove two triangles congruent?Read the answer and worked solution →Two triangles have all three angles equal. What must be true of them?Read the answer and worked solution →Two right triangles have equal hypotenuses and one other pair of equal sides. Which rule applies?Read the answer and worked solution →Why can the AAS rule be treated as the ASA rule?Read the answer and worked solution →The ASA congruence rule is traditionally attributed to which Greek thinker?Read the answer and worked solution →Two line segments are congruent when they have the same what?Read the answer and worked solution →A circle has diameter 10 cm and another has radius 5 cm. Are they congruent?Read the answer and worked solution →Triangle ABC is congruent to PQR as A-P, B-Q, C-R. AB=5, BC=7, CA=9 cm. Find QR + RP.Read the answer and worked solution →Triangle ABC is congruent to triangle PQR in that order. Angle A is 50° and angle B is 60°. Find angle R.Read the answer and worked solution →If triangle ABC is congruent to triangle DEF in that order, which side equals AC?Read the answer and worked solution →Two congruent triangles are cut from sheets. One has perimeter 24 cm. What is the other's perimeter?Read the answer and worked solution →Which statement about triangles is always true?Read the answer and worked solution →Triangles with sides 3, 4, 5 cm and 6, 8, 10 cm are which of these?Read the answer and worked solution →Congruent triangles have how many corresponding equalities, counting sides and angles together?Read the answer and worked solution →
Worked practice questions
An exterior angle of a triangle is 125° and one far interior angle is 70°. Find the other far interior angle.
- 45°
- 65°
- 55°
- 110°
Show answer and solution
Correct answer: C. 55°
An exterior angle equals the sum of the two interior angles not next to it, so the other angle is 125° minus 70°, which is 55°.
What is the sum of the three exterior angles of a triangle, taking one at each vertex?
- 360°
- 180°
- 540°
- 270°
Show answer and solution
Correct answer: A. 360°
Taking one exterior angle at each vertex always totals a full turn of 360° for any triangle.
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