15 degrees is not a special angle, but it is half of 30, which is a special angle.
If you need sin 15 you can use the half angle formula with 30 degrees.
With trigonometry by using the cosine rule
With trigonometry by using the cosine rule
In trigonometry, identities are mathematical expressions that are true for all values of the variables involved. Some common trigonometric identities include the Pythagorean identities, the reciprocal identities, the quotient identities, and the double angle identities. These identities are used to simplify trigonometric expressions and solve trigonometric equations.
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Unlike equations (or inequalities), identities are always true. It is, therefore, not possible to solve them to obtain values of the variable(s).
A protractor is used for measuring angles and the 3 angles in a triangle add up to 180 degrees.
To solve for the cosine (COS) of an angle, you can use the unit circle, where the cosine of an angle corresponds to the x-coordinate of the point on the circle at that angle. Alternatively, you can use trigonometric identities or the cosine function on a scientific calculator by inputting the angle in degrees or radians. For specific problem solving, using the cosine rule in triangles may also be applicable to find unknown sides or angles.
To solve for the exterior angle of a triangle, use the Exterior Angle Theorem, which states that the measure of an exterior angle is equal to the sum of the measures of the two non-adjacent interior angles. To apply this, identify the exterior angle and the two corresponding interior angles. Simply add the measures of those two interior angles together to find the value of the exterior angle. For example, if the interior angles are 40° and 60°, the exterior angle would be 40° + 60° = 100°.
by proving l.h.s=r.h.s
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A bisected angle refers to an angle that has been divided into two equal parts by a line or ray called the angle bisector. This means that each of the two resulting angles measures half of the original angle. For example, if an angle measures 80 degrees, each of the bisected angles would measure 40 degrees. Angle bisectors are commonly used in geometry to solve problems related to angle measurements and constructions.
No, you do not need to know all the side lengths and angle measures to solve a triangle. You can solve a triangle using various methods, such as the Law of Sines or the Law of Cosines, if you have sufficient information, like two angles and one side (AAS or ASA), or two sides and the included angle (SAS). Additionally, having all three side lengths (SSS) is also enough to determine the triangle's angles.