Question

What is the value of y?

Answer 1

1.) Set up an equation.

All of the angles in a triangle have a sum of 180°. This means that in order to solve this problem, you have to add up all of the angle measures. Since we already know they add up to 180°, then the algebraic equation will look like:

$y + y - 12 + 56 = 180$

2.) Simplify.

We can see that there are two variables and two known numbers. To make the equation simpler, add up the numbers that are compatible with each other.

$(y + y) + (-12 + 56) = 180$

--> $2y + 44 = 180$

3.) Isolate y.

If 180 is 44 more than 2y, then that means we can flip this and say that 2y is 44 less than 180. Numerically, this would be:

$2y + 44 = 180$

--> $2y + 44 - 44 = 180 - 44$

---> $2y = 136$

Isolate y using the same concept.

$\frac{2y}{2} = \frac{136}{2}$

--> $y = \frac{136}{2}$

We are left with $y = 68$.

4.) Check your work.

Now that we know the value of y, all that's left to do is to plug in the value to see if your answer is true.

$(68) + (68) - 12 + 56 = 180$

--> $136 - 12 + 56 = 180$

---> $124 + 56 = 180$

So we know it is true that y = 68°. Hope this was helpful.