Check sibling questions

Sum of angles of a triangle is 180°

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Here,

∠A + ∠B + ∠C = 180°   

For proof, please check Theorem 6.7

Let’s solve some examples

 

Show that sum of angles of the triangle is 180°

Angle sum property of a triangle - Part 2

Sum of all angles of triangle = ∠A + ∠B + ∠C

= 30° + 80° + 70°

= 110° + 70°

= 180°        

 

Show that sum of angles of the triangle is 180°

Angle sum property of a triangle - Part 3

Sum of all angles of triangle = ∠P + ∠Q + ∠R

= 40° + 120° + 20°

= 180°        

 

Show that sum of angles of the triangle is 180°

Angle sum property of a triangle - Part 4

Sum of all angles of triangle = ∠X + ∠Y + ∠Z

= 45° + 90° + 45°

= 180°        

 

Find the missing angle of following triangles

Angle sum property of a triangle - Part 5

In ∆ABC,

  ∠A + ∠B + ∠C = 180°               (Angle sum property of triangle)

  55° + 75° + ∠C = 180°

  130° + ∠C = 180°

  ∠C = 180°  − 130°

  ∠C = 50° 

 

Find the missing angle of following triangles

Angle sum property of a triangle - Part 6

In ∆PQR,

  ∠P + ∠Q + ∠R = 180°       (Angle sum property of triangle)

  30° + ∠Q + 50° = 180°

    ∠Q + 80° = 180°

    ∠Q = 180°  − 80°

   ∠Q = 100° 

 

Find the missing angle of following triangles

Angle sum property of a triangle - Part 7

In ∆XYZ,

  ∠X + ∠Y + ∠Z = 180°         (Angle sum property of triangle)

  20° + 90° + ∠Z  = 180°

   110° + ∠Z = 180°

   ∠Z = 180° − 110°

  ∠Z = 70°

 

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.