Lines Angles and Triangles (Class 7)

What this worksheet covers

This is an eighteen-question practice worksheet on lines, angles and triangles for Class 7, written to the pattern of the SOF International Mathematics Olympiad (IMO). It carries 24 marks and is designed to be attempted in 45 minutes, split across three sections — Mathematical Reasoning, Everyday Mathematics and Reasoning and Achievers Section. Every question is multiple choice with exactly one correct option, and every one comes with a fully worked solution rather than just an answer key — so a child who gets one wrong can see where the reasoning went astray instead of only learning that it did.

Skills your child practises

• Applied problem-solving on lines, angles and triangles at Class 7 level
• Working accurately against a time limit, as the real paper demands
• Mathematical Reasoning questions in the olympiad format
• Everyday Mathematics and Reasoning questions in the olympiad format
• Achievers Section questions in the olympiad format
• Reading worked solutions to find the step that went wrong

How to use it

1. 1There are 18 questions in this worksheet. All questions are compulsory.
2. 2Each question has four options (A), (B), (C) and (D). Exactly one option is correct.
3. 3Questions 1–15 carry 1 mark each. Questions 16–18 (Achievers Section) carry 3 marks each.
4. 4There is no negative marking. Use of a calculator is not allowed.
5. 5Figures are not drawn to scale.

Sample questions from this worksheet

A preview of what's inside Lines Angles and Triangles (Class 7) — the PDF has the full set, and every question comes with a worked solution like these.

1. 1. Two angles whose sum is 90° are called _______ angles.

   • AComplementarycorrect
   • BSupplementary
   • CVertically opposite
   • DAdjacent
   Solution: Complementary angles add up to 90°. Supplementary angles add up to 180°.

2. 2. Two angles of a triangle are 43° and 67°. What is the exterior angle at the third vertex?

   • A70°
   • B137°
   • C113°
   • D110°correct
   Solution: By the exterior angle property, the exterior angle equals the sum of the two interior opposite angles.
   43° + 67° = 110°.
   (Check: the third interior angle is 180° − 110° = 70°, and 70° + 110° = 180°. ✓)

3. 3. Consider the following statements.(i) Vertically opposite angles are always equal.(ii) Two acute angles can be supplementary.(iii) An exterior angle of a triangle is always greater than each interior opposite angle.Which of the statements is/are correct?

   • A(i) and (ii) only
   • B(ii) and (iii) only
   • C(i) and (iii) onlycorrect
   • DAll three
   Solution: Statement (i) is true. Statement (ii) is false — two acute angles are each below 90°, so their sum is below 180° and they can never be supplementary. Statement (iii) is true, since the exterior angle equals the sum of the two interior opposite angles and each of those is positive. Hence (i) and (iii).