What is the value of y? enter your answer in the box.

5

Explanation:

So for these, a triangle always equals 180 so you just have to set it up where you add all the sides together to equal 180. Also because it is an isosceles triangle, it means that the two bottom angles are equal so start by setting them equal and solving for x:

75 = 3x

So divide both sides by 3:

25 = x

Now you really didn't have to solve for x because you already know that it equals 75, so you could just said x doesn't matter and just treat it like a 75, but I explained it just in case.

So now that you have your base angles which added together equal 150 lets set it all equal to 180:

4y + 10 + 150 = 180

Now I will simplify this:

4y + 160 = 180

subtract 160 from both sides:

4y = 20

now divide both sides by 4:

y = 5

hope this helps!