Q1
The sum of angles in a triangle is:
A180°
B360°
C90°
D270°
CBSEClass 7 (CBSE)MathematicsCh 7 · Topic 1
Properties of a Triangle's Angles
Learning key properties relating to the angles of a triangle.
Core concept
This property can be demonstrated practically by tearing off the three corners of a paper triangle and arranging them together — they will always form a straight line (180°). This angle sum property is essential for solving many geometry problems, verifying whether a triangle's angles are correctly measured, and forms the basis for angle-related properties in other polygons, since any polygon can be divided into triangles to calculate its total angle sum.
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CBSE class 7 properties of a triangle's angles
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• The sum of the angles in any triangle is always 180°.
• This can be demonstrated by tearing a paper triangle's corners and arranging them into a straight line.
• The third angle can be found by subtracting the sum of the other two from 180°.
• This property forms the basis for finding angle sums in other polygons.