Question

Shown is a regular pentagon, find y.

Answer 1

As we know that,

`\star` Each angle of regular pentagon = 108°.

The triangle given to us is a Isosceles Triangle.

In the given triangle,

`\longrightarrow\rm{y + y + 108 = 180 \: ... \: (Angle \: sum \: property)} \\ \\ \longrightarrow\rm{2y + 108 = 180} \\ \\ \longrightarrow\rm{2y = 180 - 108} \\ \\ \longrightarrow\rm{2y = 72} \\ \\ \longrightarrow\rm{y = \frac{\cancel{72}}{\cancel{2}}} \\ \\ \longrightarrow\rm{y = 36} \: \bigstar`

Henceforth;

• The value of y is 36.

Answer 2

Explanation:

Each angle of regular pentagon = 108

Given triangle is an isosceles triangle

In this triangle,

y + y + 108 = 180 {angle sum property}

2y + 108 = 180

2y = 180 - 108

2y = 72

y = 72/2

y = 36