Difference between revisions of "AA similarity"

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==Proof==
 
==Proof==
 
Let ABC and DEF be two triangles such that <math>\angle A = \angle D</math> and <math>\angle B = \angle E</math>.
 
Let ABC and DEF be two triangles such that <math>\angle A = \angle D</math> and <math>\angle B = \angle E</math>.
The sum interior angles of a triangle is equal to 180. <math>\angle A + \angle B + \angle C = 180</math> and
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The sum interior angles of a triangle is equal to 180. Therefore, <math>\angle A + \angle B + \angle C = 180</math>, and
<math>\angle D + \angle E + \angle F = 180</math>  
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<math>\angle D + \angle E + \angle F = 180</math>.
Thus, we can write the equation: <math>\angle A  + \angle B + \angle C=\angle D + \angle E + \angle F \Longrightarrow
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We can write the equation: <math>\angle A  + \angle B + \angle C = 180 = \angle D + \angle E + \angle F \Longrightarrow
\angle D + \angle E + \angle C = \angle D + \angle E + \angle F</math>, since we know that <math>\angle A = \angle D</math> and <math>\angle B = \angle E</math>, from before.
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\angle D + \angle E + \angle C = \angle D + \angle E + \angle F</math>, acknowledging the fact that <math>\angle A = \angle D</math> and <math>\angle B = \angle E</math>.
Therefore, by subtracting <math>\angle D + \angle E</math> by both equations, we get <math>\angle C = \angle F</math>.
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To conclude, by subtracting <math>\angle D + \angle E</math> by both equations, we get <math>\angle C = \angle F</math>.
  
  

Latest revision as of 01:18, 24 December 2022

Theorem: In two triangles, if two pairs of corresponding angles are congruent, then the triangles are similar.

Proof

Let ABC and DEF be two triangles such that $\angle A = \angle D$ and $\angle B = \angle E$. The sum interior angles of a triangle is equal to 180. Therefore, $\angle A + \angle B + \angle C = 180$, and $\angle D + \angle E + \angle F = 180$. We can write the equation: $\angle A  + \angle B + \angle C = 180 = \angle D + \angle E + \angle F \Longrightarrow \angle D + \angle E + \angle C = \angle D + \angle E + \angle F$, acknowledging the fact that $\angle A = \angle D$ and $\angle B = \angle E$. To conclude, by subtracting $\angle D + \angle E$ by both equations, we get $\angle C = \angle F$.


See also

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