- Books Name
- CBSE Class 7 Mathematics Book
- Publication
- Param Publication
- Course
- CBSE Class 7
- Subject
- Mathmatics
Triangle
A triangle is a closed figure made by three line segments. It has three vertices, three sides and three angles.
A triangle ABC is given having three vertices A, B, C and three sides AB, BC, CA and three angles are ∠ABC, ∠ BCA, ∠CAB.
Classification of triangles:
1. With respect to angles are:
(a) Acute-angled triangles
(b) Obtuse-angled triangles
(c) Right-angled traingles
(a) Acute-angled triangles
A triangle in which measurement of each of the three angles are less than 90°.
(b) Obtuse-angled triangle :
A triangle in which one angle is obtuse angle i.e. greater than 90° but less then 180°.
(c) Right-angled triangle:
A triangle in which one angle is exactly 90°.
• The side opposite to the right angle is called the hypotenuse.
• The other two sides are called as the legs of the right-angled triangle (or base and perpendicular).
• In the given figure AC is the hypotenuse and AB and BC are the legs of DABC.