after a deposit of $476 Sierra saves $11 per day how much money will Ciara have in 8 Days use an equation to solve the problem i
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Answer:
- 150° and 210°
- 0
Step-by-step explanation:
It is convenient to memorize the trig functions of the "special angles" of 30°, 45°, 60°, as well as the way the signs of trig functions change in the different quadrants. Realizing that the (x, y) coordinates on the unit circle correspond to (cos(θ), sin(θ)) can make it somewhat easier.
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<h3>20.</h3>You have memorized that cos(x) = (√3)/2 is true for x = 30°. That is the reference angle for the 2nd-quadrant angle 180° -30° = 150°, and for the 3rd-quadrant angle 180° +30° = 210°.
Cos(x) is negative in the 2nd and 3rd quadrants, so the angles you're looking for are
150° and 210°
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<h3>Bonus</h3>You have memorized that sin(π/4) = √2/2, and that cos(3π/4) = -√2/2. The sum of these values is ...
√2/2 + (-√2/2) = 0
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<em>Additional comments</em>
Your calculator can help you with both of these problems.
The coordinates given on the attached unit circle chart are (cos(θ), sin(θ)).
Answers:
Reason 4: Isosceles triangle
Reason 5: Segment Addition Postulate
Reason 6: Segment Addition Postulate
Reason 7: Substitution
Reason 8: Substitution
Reason 9: Subtraction property of equality
Reason 10: Definition of congruence
Reason 11: Vertical Angles Theorem
Reason 12: Vertical Angles Theorem
Reason 13: ASA (angle side angle) congruence theorem
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Explanations:
Reason 4: Triangle DCE is an isosceles triangle because of statement 1 of the proof table. The congruent base angles lead to congruent opposite sides.
Reason 5 and 6: This is the idea of breaking any segment into smaller pieces. The smaller pieces glue back together to get the larger original segment.
Reasons 7 and 8: Substitution is a math term which means "replacement". So for instance, in line 7 we started with DB = DC + CB (from line 6), then we replaced the "DB" with "DF" (see line 3); and then replaced "DF" with "DE+EF"
Reason 9: In this step, we subtract DE from both sides to have it go away and cancel out
Reason 10: If two lengths are equal, then the segments are congruent
Reason 11 & 12: Two angles are vertical if they are opposite from one another after forming from two lines crossing. Think of an X shape. Vertical angles are congruent.
Reason 13: We have two pairs of congruent angles, and a pair of congruent sides. The sides are between the angles. The order is important. See the attached image below.
