Choose the possible descriptions of cross sections formed by the intersection of a plane and a cylinder. circle

rectangle

triangle

line segment

point

Circle is the right answer for this question.

the sum of all the angles in a triangle are equal to 180

so you can add   the 3 given angles together to equal 180:

5y + 2y + 2y = 180

or since all three angles have the same letter, combine the 3 angles to equal 180:

9y = 180