Law of cosines
When none of the angles are known, and using Pythagoras, the triangle is known not to be right angled.
In trigonometry sines and cosines are used to solve a mathematical problem. And sines and cosines are also used in meteorology in estimating the height of the clouds.
Yes. Look up the law of sines and the law of cosines as examples. there are also formulas that can find out the area of a non-right triangle.
Label the angles of the triangle A, B, and C. Label the side opposite angle A side a, the one opposite angle B side b, and the one opposite angle C side c. Let's say you want to solve for angle A, you use the law of cosines: a^2=b^2+c^2-2bcCosA CosA is the "variable" in this equation, so isolate this. When you have that, you'll have some number (let's call it D) equal to CosA: D=CosA Use the inverse Cos function to find the measure of the angle: Cos^-1(D)=A And you have the measure of angle A. From here you can either use the law of cosines again to find a second angle and then the third, though the easier route is usually to just use the law of sines for find the second angle and then the fact that all three angles add to 180 to find the third.
Trigonometric ratios, by themselves, can only be used for right angled triangles. The law of cosines or the sine law can be used for any triangle.
Law of cosines
The law of cosines with a right angle is just the pythagorean theorem. The cosine of 90 degrees is 0. That is why the hypotenuse squared is equal to the sum of both of the legs squared
The law of cosines can be written in one form as: c2 = a2 + b2 - 2abCos C. Without 3 of the 4 variables being given, there is no way to answer this question.
cosine = adjacent/hypotenuse
Yes
No, it applies to all triangles.
D. The Pythagorean Theorem
Yes
No, it applies to all triangles.
It follows from the cyclical symmetry of the cosine rule.
We use the law of Cosines to be able to find : 1. The measure of the third side, when the measure of two sides and the included angle of a triangle ABC are known. 2. The measure of any angle, when the measure of the three sides of a triangle ABC are known.