Question

I’m really confused please help me

Answer 1

Answer:  54

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Explanation:

Focus on the bottom most triangle. The upper angle of this triangle is 360/5 = 72 degrees. This is because the regular pentagon is split into five congruent (aka identical) triangles.

Each of the triangles are isosceles. Let x be the measure of the base angles.

Use the rule that adding the three angles of a triangle gets us 180

angle1+angle2+angle3 = 180

x+x+72 = 180

2x+72 = 180

2x = 180-72

2x = 108

x = 108/2

x = 54 is the answer

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Another way to get the answer:

i = interior angle of a regular polygon with n sides

i = 180(n-2)/n

i = 180(5-2)/5

i = 180(3)/5

i = 540/5

i = 108

Each interior angle of a regular pentagon is 108 degrees.

Angle x marked in blue is half that, so it is 108/2 = 54 degrees

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A third method:

E = exterior angle of a regular polygon with n sides

E = 360/n

E = 360/5

E = 72 degrees is the measure of each exterior angle

i = 180 - E

i = 180-72

i = 108 is the measure of each interior angle.

To wrap things up, we follow the same exact steps at the end of the 2nd section to get 108/2 = 54 as our answer.