4.MD.C.5

Recognize angles as geometric shapes that are formed wherever two rays share a common endpoint, and understand concepts of angle measurement.

Students will learn an angle is composed of two rays sharing an endpoint, called the vertex of the angle. Students will also learn that the word angle comes from the Latin word angulus, meaning corner. Also, students will learn how to visually compare angles. A lesson on all of the aforementioned is here. Students can practice visually comparing measures of angles here.

Note: What are *concepts of angle measurement?* This Common Core standard is so vague.