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Published byJayson Shelton Modified over 9 years ago
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Think back to geometry and write down everything you remember about angles.
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Mr. Szwast has meetings after school on the following days, and therefore will not be available: Wednesday, February 3 Monday, February 8
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Section 4.1 NO CALCULATORS!
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A ray is a part of line that has one endpoint and extends forever in one direction (arrow) An angle is formed by two rays that have a common endpoint, called the vertex The initial side of an angle is where it starts The terminal side of an angle is where it ends A Θ B C Terminal Side Initial Side Vertex
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An angle is in standard position if its vertex is at the origin of a rectangular coordinate system and its initial side lies along the positive x-axis. x y Terminal Side Initial Side Vertex is positive Positive angles rotate counterclockwise. x y Terminal Side Initial Side Vertex is negative Negative angles rotate clockwise.
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The rectangular coordinate plane is divided into four quadrants
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DegreesRadians Defined as 1/360 th of a full rotation 360˚ in a circle Converted to radians by multiplying by Defined as the measure of the central angle of a circle that intercepts an arc equal in length to the radius of the circle 2π radians in a circle Converted to degrees by multiplying by
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An acute angle measures less than 90˚ ( π/2 radians) A right angle measures exactly 90˚ ( π/2 radians) ◦ Often indicated by a small square at the vertex An obtuse angle measures between 90˚ and 180˚ ( π/2 and π radians) A straight angle measures exactly 180˚ ( π radians) Acute angle 0º < < 90º 90º Right angle 1/4 rotation Obtuse angle 90º < < 180º 180º Straight angle 1/2 rotation
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Convert to radians Draw each angle in standard position. Identify in which quadrant the angle lies.
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Convert the following angles to radians
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Convert to radians Draw each angle in standard position. Identify in which quadrant the angle lies.
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Convert to degrees Draw each angle in standard position. Identify in which quadrant the angle lies.
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Convert to degrees Draw each angle in standard position. Identify in which quadrant the angle lies.
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Coterminal angles have the same initial and terminal sides. Coterminal angles differ by a multiple of 360˚ or 2 π An angle of x is coterminal with angles where k is an integer
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Find a positive angle less than 360˚ or 2 π that is coterminal with:
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Read Section 4.1 Page 434 #1-73 odd
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Convert the following angles to radians
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Complete the table DegreesRadians 300º -120º
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Find a positive angle less than 360˚ or 2 π that is coterminal with:
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Two positive angles are complements if their sum is 90˚ ( π /2) ◦ Complement of x˚ = 90˚- x˚ ◦ Complement of x = π /2 – x Two positive angles are supplements if their sum is 180˚ ( π ) ◦ Supplement of x˚ = 180˚- x˚ ◦ Supplement of x = π – x
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If possible, find the complement and supplement of each angle
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AngleComplementSupplement a) b) c) d)
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Find the radian measure of the central angle of a circle of radius 6 yards that intercepts an arc of length 8 yards.
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Find the arc length of a circle of radius 8 feet intercepted by a central angle of 225°.
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Read Section 4.1 Page 434 #1-73 odd Read Section 4.2
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You have the remainder of class today for the Making Waves Activity.
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