Question

one angle on the base of an isosceles triangle is 30°.what is the measure of its vertical angle​

Answer 1

Answer:

120° is the vertical angle

Step-by-step explanation:

base angles of isosceles triangle are equal

the two base angles are 30° and 30°

sum of all angles of triangle = 180°

30° + 30° + x = 180°

60° + x = 180°

x = 180 - 60

x = 120°

therefore the measure of vertical angle = 120°

hope you get your answer

Answer 2

We know that the base angles of an isosceles triangle are equal. This is of the theorem that says," In a triangle, equal opposite sides have equal opposite angles."

Let the vertical angle be x,

$\therefore 30\° +30\°+\angle x=180\°\\\Rightarrow \angle x=120\°$

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