Consider the figure below. Abraham cut regular pentagon ABCDE into quadrilateral BEGC. Which of the following statements is true about quadrilateral BEGC? (picture included)

Consider the figure below Abraham cut regular pentagon ABCDE into quadrilateral BEGC Which of the following statements is true about quadrilateral BEGC picture class=

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frika

Answer:

Correct: 2, 3, 4, 6

Step-by-step explanation:

ABCDE is a regular pentagon. The sum of the measures of all interior angles in the pentagon is

[tex](n-2)\cdot 180^{\circ}=(5-2)\cdot 180^{\circ}=540^{\circ},[/tex]

then the measure of each interior angles in the regular pentegon is

[tex]\dfrac{540^{\circ}}{5}=108^{\circ}[/tex]

Triangle ABe is isosceles triangle, so the adjacent to the bas BE angle has the measure

[tex]m\angle ABE=\dfrac{180^{\circ}-108^{\circ}}{2}=36^{\circ}[/tex]

Therefore,

[tex]m\angle CBE=m\angle ABC-m\angle ABE=108^{\circ}-36^{\circ}=72^{\circ}[/tex]

(option 2 is correct)

Since [tex]m\angle BCG=108^{\circ},[/tex] then

[tex]m\angle EGC=108^{\circ }+4x[/tex]

The sum of the measures of all interior angles in quadrilateral BCGE is

[tex](n-2)\cdot 180^{\circ}=(4-2)\cdot 180^{\circ}=360^{\circ},[/tex]

(option 6 is correct), then

[tex]m\angle CBE+m\angle BEG+m\angle EGC+m\angle BCG=360^{\circ}\\ \\72^{\circ}+19x+3^{\circ}+108^{\circ}+4x+108^{\circ}=360^{\circ}\\ \\23x=69^{\circ}\\ \\x=3[/tex]

(option 1 is false)

[tex]m\angle EGC=108^{\circ}+4\cdot 3^{\circ}=120^{\circ}[/tex]

(option 3 is correct)

[tex]m\angle GCB+m\angle EGC=108^{\circ}+72^{\circ}=180^{\circ}[/tex]

(option 4 is correct)

[tex]m\angle BEC+m\angle EGC=(19\cdot 3+3+108+4\cdot 3)^{\circ}=180^{\circ}[/tex]

(option 5 is false)