Respuesta :

The answer is:  " 60° " .
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     " m∠A = 60° " .
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Explanation:
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Note:  All triangles, by definition, have 3 (three) sides and 3 (three angles).

The triangle shown (in the "image attached") has three EQUAL side lengths.   Therefore, the triangle shown is an "equilateral triangle" and has 3 (three) equal angles, as well.

All triangles by, definition, have 3 (three) angles that add up to "180° " .

Since each of the 3 (three) angles is equal;  and the three angles are:  

  "∠A" , "∠B" , and "∠C" ;

We can find the measure of "∠A" ; denoted as:  "m∠A" ; as follows:
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    m∠A  = 180° ÷ 3 = 60° .
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The answer is:  " 60° " .
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   m∠A = " 60° " .
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