On a coordinate plane, triangle A B C is shown. Point A is at (negative 1, 6), point B is at (negative 1, 1), and point C is at (2, 2). Triangle ABC is an isosceles triangle in which AB = AC. What is the perimeter of △ABC?

5 + StartRoot 10 EndRoot units
StartRoot 10 EndRoot units
10 + StartRoot 10 EndRoot units
15 units

Option C.

Step-by-step explanation:

Assume that the below figure attached with this question.

Distance formula:

From the below figure it is clear that the vertices of triangle are A(-1,6), B(-1,1) and C(2,2).

Using distance formula we get

Similarly,

The perimeter of △ABC is

The perimeter of △ABC is .

Therefore, the correct option is C.