Answer: C. 40°
Step 1: Determine the type of triangle
The shape in the picture is an isosceles triangle. This is determined because two sides share the same length. This will mean that two angles will also share the same measurement, helping us to find our answer.
Step 2: Write an equation
Now that we have identified the type of triangle, we can write an equation to solve. Two angles will be equal to 70, so subtract 70 twice from 180. It will be taken away from 180, since in a triangle the three angles are equal to 180 degrees. Now we can write the equation!
X= 180-70-70
Step 3: Solve for ∠x
The final step will be to solve using the equation we have created before.
X= 180-70-70
X= 110-70
X= 40
There is the final answer. Hope this helps! Comment below for more questions.