Question

the measure of the first angle is twice the measure of the second angle. The measure of the third angle is 12 degrees more than the measure of the second angle. What is the measure of each angle?

Answer 1

Let us assume that
second angle = x
first angle = 2x
third angle = 12+x
we know by angle sum property, sum of all angles of a triangle is 180 degrees.
so our equation becomes :
2x+x+(12+x) = 180

solve for x and get the answer.
(note: i chose second angle x for simplicity, because if we would have chosen first angle x den second would have been (x/2))

If you haven't understand how i did this, ask.