Grade 4 - Angle Measurement Unit
The Angle Measurement Unit connects measurement to geometry in order to answer questions such as:
- What is an angle? How can angles be measured? How is estimation important in measuring angles?
- How are angle measures used to identify 2-dimensional geometric figures?
Math Concepts and Skills:
The student solves problems involving angles less than or equal to 180 degrees.
The student:
- recognizes that angles are formed wherever two rays share a common endpoint.
- understands that an angle is the part of a circle that is "cut out" by the rays of the angle and the common endpoint of the rays is the center of the circle.
- defines a degree as the unit used to measure an angle; i.e. 1/360 of any circle is one degree. An angle that "cuts" n/360 out of any circle whose center is at the angle's vertex has a measure of n degrees.
- determines the approximate measures of angles in degrees to the nearest whole number using a protractor and draws an angle with a given measure.
- finds the measure of an unknown angle formed by two non-overlapping adjacent angles given one or both angle measures.
Summative Assessment Task
Given a picture of a protractor with several angels drawn on it, students determine three pairs of angles that would equal the sum of 140 degrees.
Instructional Tasks/Formative Assessments
Given the fact that if you hold your fist straight in front of you, the distance between the bottom of your fist and the top of your fist measures about ten degrees above the horizon, students determine if Jupiter will appear six fists above the horizon at 9 o'clock p.m.
Given a set of angles, students determine if two angles are acute angles.
Given one angle measurement, students determine the measurements of three other angles.
Using five different colors, students create a game spinner that gives each person playing the game a fair chance to win.