I use this PowerPoint as a review of Geometry terms (right, obtuse, acute angles, lines, line segments, rays, perpendicular, parallel, and intersecting lines, quadrilaterals and polygons). You can just have students write A, B, or C onto a whiteboard or you can use the Kagan "Show Down" strategy. This is where one student will be the "sheriff." The sheriff will read the question on the PP. Then everyone responds on their whiteboard (including the sheriff). Once students have an answer on their board, they put a thumbs up. The sheriff looks to see if everyone has a thumbs up. When they do, they call "Show Down" and students will show their responses. After I display the correct answer, I have students "coach or celebrate" with their thinking partner. During that turn and talk, partners basically explain their thinking.