Georgia Performance Standards (GPS – 4th grade)
M4M2 Students will understand the concept of angle and how to measure angles:
a. Use tools, such as protractor or angle ruler
M4G1 Students will define and identify the characteristics of geometric figures through examination and construction:
a. Examine and compare angles in order to classify and identify triangles by their angles.
National Council for Teachers of Mathematics (NCTM)
Measurement Standard for Grades 3–5
Students will understand measurable attributes of objects and the units, systems, and processes of measurement. Students will learn that a “square corner” is called a right angle and establish this as a benchmark for estimating the size of other angles.