Triangle abc is an isosceles triangle in which ab = ac. what is the perimeter of △abc?
5 + square root of 10 units

3x square root of units

10 + square root of 10 units

15 units

perimeter = 10 + √10 units

Explanation:
First, we will need to get the length of each line using the distance formula which is as follows:
distance = 

1- length of AB:
AB =  = 5 units

2- length of AC
length of AC is the same as AB = 5 units

3- length of BC:
BC =  = √10 units

Now, we can get the perimeter by adding the side lengths as follows:
perimeter = 5 + 5 + √10
perimeter = 10 + √10 units

Hope this helps :)