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Angles, Angles, Everywhere. Mrs. Keen 6 th grade Math dkeene@twu.edu. Just warming up…. Identify each object as containing an acute, right, or obtuse angle Right Obtuse Acute. Learning Objectives.
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Angles, Angles, Everywhere Mrs. Keen 6th grade Math dkeene@twu.edu
Just warming up… Identify each object as containing an acute, right, or obtuse angle Right Obtuse Acute
Learning Objectives • The student will use angle measurement to classify angles as acute, right, or obtuse (TEKS 6.6a) • The student will identifyrelationships involving angles in triangles and quadrilaterals (TEKS 6.6b)
Vocabulary to Know • Acute angle – an angle less than 90° • Angle – two rays with a common endpoint • Degree – unit of measure for angles °
Angle Vocab con’t… • Obtuse angle– an angle greater than 90° • Straight angle – an angle whose measure is exactly 180°
Shapes, Shapes, & More Shapes • Polygon – a geometric figure made up of three or more line segments that intersect only at their endpoints • Vertex (pl. vertices) – the common endpoint of the two rays form an angle
Shapes con’t… • Triangle – a polygon with three sides and three vertices • Quadrilateral– a polygon with four sides and four vertices
Quadrilaterals • Square – a polygon with four equal sides and four right angles • Rectangle – a polygon with four right angles and four sides
Quadrilaterals con’t… • Trapezoid – a quadrilateral with exactly one pair of parallel sides • Parallelogram– a quadrilateral with exactly two pairs of parallel sides
Angles and Triangles • The sum of all angles in a triangle equals 180° 80° + 50° + 50° = 180° 90° + 45° + 45° = 180° 110° + 45° + 25° = 180° 110° 80° 45° 25° 45° 90° 45° 50° 50°
So…. If we know that the sum of all angles in a triangle equals 180°, then… What is the measure of the missing angles? 72° + 78° + ? = 180° 45° + 45° + ? = 180° 115° + 35° + ? = 180° 180° - 150° = 30° 180° - 90° = 90° 180° - 150° = 30° 115° 35° 45° 72° ? ? 78° 45° ?
Triangles vs. Squares and Rectangles Since a square can be divided into two triangles, then… the sum of all angles in a square is 360°, because 180° + 180° = 360° Since a rectangle can be divided into two triangles, then… the sum of all angles in a rectangle is 360°, because 180° + 180° = 360° 180° 180° 360° 360° 180° 180°
Triangles vs. Parallelograms and Trapezoids Since a parallelogram can be divided into two triangles, then… the sum of all angles in a parallelogram is 360°, because 180° + 180° = 360° Since a trapezoid can be divided into two triangles, then… the sum of all angles in a trapezoid is 360°, because 180° + 180° = 360° 180° 180° 360° 360° 180° 180°
So… If we know that the sum of all angles in a square, rectangle, parallelogram, and trapezoid equals 180°, then… What is the measure of the missing angles? 90° + 90° + 90° + ? = 180° 90° + 90° + 90° + ? = 180° 360° - 270° = 90° 360° - 270° = 90° 110° + 70° + 110° + ? = 180° 110° + 70° + 70° + ? = 180° 360° - 290° = 70° 360° - 250° = 110° 90° 90° ? 90° 110° ? 70° 110° 90° 90° 90° ? 70° 110° ? 70°
Now its your turn… You will be going out onto the playground and will search for “real life” examples of acute, obtuse, and right angles. • Separate into your assigned groups • Decide which group member will be the record keeper • Head out to the playground, you will have 15 minutes to gather as many items as you can