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Question 3 - Figure it out - Page 165 - Sum of angles of a triangle - Chapter 7 Class 7 - A tale of three Intersecting Lines (Ganit Prakash)
Last updated at November 7, 2025 by Teachoo
Class 7 (Ganita Prakash & Old NCERT)
Chapter 7 Class 7 - A tale of three Intersecting Lines (Ganit Prakash)
- Definition
- Constructing Equilateral Triangle
- Constructing a Triangle when its Sides are given
- Figure it out - Page 150, 151
- Are Triangles Possible for any Lengths?
- Figure it out - Page 154
- Visualising the Construction of Circles
- Figure it out - Page 156
- Triangle Inequality & Construction of Circles
- Figure it out - Page 159
- Constructing Triangle when 2 Sides and the Included Angle are given
- Constructing Triangle when 2 Angles and the Included Side are given
- Do triangles always exist?
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Sum of angles of a triangle
- Angle Sum Property
- Exterior Angles
- Constructions Related to Altitudes of Triangles
- Figure it out - Page 170, 171
Transcript
Question 3 - Figure it out - Page 165 Here is a triangle in which we know ∠B = ∠C and ∠A = 50°. Can you find ∠B and ∠C? Let ∠ B = ∠ C = x° Now, by alternate interior angles ∠XAB = x° ∠YAC = x° Since XY is a line Applying Linear Pair ∠ XAB + ∠ A + ∠ YAC = 180° x° + 50° + x° = 180° 50 + 2x = 180° 2x = 180 – 50 2x = 130 x = (130° )/2 x = 65° Thus, ∠ B = ∠ C = 65° Thus, ∠ B = ∠ C = 65°
