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Splash Screen. Five-Minute Check (over Lesson 12–1) CCSS Then/Now New Vocabulary Key Concept: Angle Measures Example 1: Draw an Angle in Standard Position Example 2: Real-World Example: Draw an Angle in Standard Position Example 3: Find Coterminal Angles
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Five-Minute Check (over Lesson 12–1) CCSS Then/Now New Vocabulary Key Concept: Angle Measures Example 1: Draw an Angle in Standard Position Example 2: Real-World Example: Draw an Angle in Standard Position Example 3: Find Coterminal Angles Key Concept: Convert Between Degrees and Radians Example 4: Convert Between Degrees and Radians Concept Summary: Degrees and Radians Key Concept: Arc Length Example 5: Real-World Example: Find Arc Length Lesson Menu
A. B. C. D. Find sin , cos , and tan . 5-Minute Check 1
A. B. C. D. Find csc , sec , and cot . 5-Minute Check 2
Find the value of a. A. 13.9 B. 12.3 C. 6.9 D. 4.5 5-Minute Check 3
Find the measure of B. A. 30° B. 45° C. 60° D. 90° 5-Minute Check 4
Find the value of c. A. 13.9 B. 12.3 C. 9.1 D. 6.9 5-Minute Check 5
A.ℓ = 3 sin 15° B.ℓ = 3 cos 15° C.ℓ D.ℓ David needs a ramp that rises to a height of 3 feet at a 15° angle. Write an equation for the length ℓ of the ramp. 5-Minute Check 6
At a construction site, the workers need to build a ramp up to the second story of a house. The angle of inclination of the ramp cannot be more than 20°. Find the length of the ramp if the distance to the second story is 15 feet. A. 5.13 ft B. 15.96 ft C. 41.21 ft D. 43.86 ft 5-Minute Check 7
Content Standards F.TF.1 Understand radian measure of an angle as the length of the arc on the unit circle subtended by the angle. Mathematical Practices 2 Reason abstractly and quantitatively. CCSS
You used angles with degree measures. • Draw and find angles in standard position. • Convert between degree measures and radian measures. Then/Now
standard position • initial side • terminal side • coterminal angles • radian • central angle • arc length Vocabulary
Draw an Angle in Standard Position A. Draw an angle with a measure of 210° in standard position. 210° = 180° + 30° Draw the terminal side of the angle 30° counterclockwise past the negative x-axis. Answer: Example 1
Draw an Angle in Standard Position B. Draw an angle with a measure of –45° in standard position. The angle is negative. Draw the terminal side 45° clockwise from the positive x-axis. Answer: Example 1
A.B. C.D. A. Draw an angle with a measure of 225° in standard position. Example 1
A.B. C.D. B. Draw an angle with a measure of –60° in standard position. Example 1
Draw an Angle in Standard Position A. DIVING In a springboard diving competition, a diver made a 900-degree rotation before slicing into the water. Draw an angle in standard position that measures 900°. Answer: 900° = 360° + 360° + 180° Draw the terminal side of the angle 180° past the positive x-axis. Example 2
SNOWBOARDING While riding down the mountain, a snowboarder goes off a jump and turns 600° before touching down onto the snow again. Determine how many degrees past the positive x-axis the snowboarder lands. A. 120° B. 180° C. 240° D. 300° Example 2
Find Coterminal Angles A. Find an angle with a positive measure and an angle with a negative measure that are coterminal with 210°. positive angle: 210° + 360° = 570° negative angle: 210° – 360° = –150° Answer: 570° and –150° Example 3
Find Coterminal Angles B. Find an angle with a positive measure and an angle with a negative measure that are coterminal with –120°. positive angle: 120° + 360° = 240° negative angle: 120° – 360° = –480° Answer: 240° and –480° Example 3
A. Find an angle with a positive measure and an angle with a negative measure that are coterminal with 330°. A. –30°, 690° B. –30°, 630° C. –60°, 630° D. –60°, 720° Example 3
B. Find an angle with a positive measure and an angle with a negative measure that are coterminal with –80°. A. –380°, 220° B. –440°, 280° C. –320°, 380° D. –400°, 300° Example 3
Convert Between Degrees and Radians A. Rewrite 30° in radians. Answer: Example 4
B. Rewrite in degrees. Convert Between Degrees and Radians Answer: –300° Example 4
A. B. C. D. A. Rewrite 45° in radians. Example 4
B. Rewrite in degrees. A. 70° B. 80° C. 30° D. 60° Example 4
Find Arc Length TRUCKS The steering wheel on a monster truck has a radius of 11 inches. How far does a point on the steering wheel travel if the wheel makes four fifths of a rotation? Step 1 Find the central angle in radians. Example 5
Find Arc Length Step 2 Use the radius and the central angle to find the arc length. s = rWrite the formula for arc length. ≈ 55.3 in.Use a calculator to simplify. Answer:A point on the steering wheel will travel about 55.3 inches after four fifths of a rotation. Example 5
BOATS The steering wheel on a yacht has a radius of 16 inches. How far does a point on the steering wheel travel if the wheel makes five sevenths of a rotation? A. 61.1 in. B. 64.6 in. C. 71.8 in. D. 74.9 in. Example 5