Respuesta :
Answer:
Add the two angles: 43° + 47° = 90°.
Step-by-step explanation:
A right triangle has an angle that equals 90°. Complementary angles equal 90°. Therefore, if you add these two angles, you will know whether or not △ABC is a right triangle. Triangle △ABC is broken up into two angles, m∠ABD and m∠DBC. When the measures m∠ABD and m∠DBC are added together, they equal 90°, and thus, form a complementary angle.
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Answer:
Givens
[tex]m\angle ABD=43\°\\m\angle DBC=47\°[/tex]
To probe [tex]\triangle ABC[/tex] is a right triangle, we have to demonstrate that the vertex B holds a right angle, that is [tex]m\angle ABC = 90\°[/tex]
Now, by sum of angles, we know
[tex]m\angle ABC = m\angle ABD + m\angle DBC[/tex]
By given we know that
[tex]m\angle ABD=43\°\\m\angle DBC=47\°[/tex]
Replacing these values, we have
[tex]m\angle ABC = 43\°+ 47\°=90\°[/tex]
Then, [tex]\angle ABC[/tex] is a right angle by definition.
Finally, [tex]\triangle ABC[/tex] is a right triangle by definition, with right angle at vertex B.