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For a triangle with sides a, b anc c, where A is the angle opposite side a, B is the angle opposite side b, etc.:
cos A = ( b2 + c2 - a2 ) / ( 2 bc )
cos B = ( a2 + c2 - b2 ) / ( 2 ac )
cos C = ( a2 + b2 - c2 ) / ( 2 ab )
These are just rearrangements of the ordinary cosine rule:
a2 = b2 + c2 - 2 bc cos A
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If you know the sum of the angles of a regular polygon how can you find the measure of one of the congruent angles?
Each interior angle = sum of angles/number of sides
How do you find angles on a right triangle?
You do not need to, if you have a right triangle that angle is 90* so the other 2 angles are 45* apiece. That is actually only partially accurate. There can be a right angled triangle with sides of 2-3-5. 5 being the hypotenuse in which the triangle's angles will not be 90-45-45 but 90-33.69-56.31. To find the angles of a right triangle, you will need to know the length of the sides. With the length of all three sides, you will need to utilize sine, cosine, and tangent to find the angles.
What shape has 3 horizontal sides?
Triangle
How do you find an angle when you know one other angle and two of the sides of a triangle?
If these two sides are opposite to these angles, and you know one of the angles, you can use the Law of Sines to find the other angle. For example, in the triangle ABC the side a is opposite to the angle A, and the side b is opposite to the angle B. If you know the lengths of these sides, a and b, and you know the measure of the angle B, then sin A/a = sin B/b multiply by a to both sides; sin A = asin B Use your calculator to find the value of arcsin(value of asin b), which is the measure of the angle A. So, Press 2ND, sin, value of asin B, ).
How do you know a rectangle is a rectangle?
It has two short sides and two long sides. The sides come in pairs of parallel lines. The sides make 4 right angles at the corners.
