Answer:
Option (3)
Step-by-step explanation:
Perimeter of a regular hexagon = 30 units
Length of one side =
= 5 units
Interior angle of hexagon =
=
= 120°
BC is an bisector of the angle measuring 120°.
m∠ABC = 60°
Similarly, m∠BCA ≅ ∠CAB ≅ 60°
Therefore, ΔABC is an equilateral triangle.
By the property of equilateral triangle, all sides of the triangle will be equal in measure.
AB ≅ BC ≅ AC ≅ 5 units
Perimeter of triangle ABC = AB + BC + AC
= 5 + 5 + 5
= 15 units
Option (3) will be the answer.