# Some Facts about Trigonometry and Euclidean Geometry

Open access

## Summary

We calculate the values of the trigonometric functions for angles: [XXX] , by [16]. After defining some trigonometric identities, we demonstrate conventional trigonometric formulas in the triangle, and the geometric property, by [14], of the triangle inscribed in a semicircle, by the proposition 3.31 in [15]. Then we define the diameter of the circumscribed circle of a triangle using the definition of the area of a triangle and prove some identities of a triangle [9]. We conclude by indicating that the diameter of a circle is twice the length of the radius

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# Formalized Mathematics

## (a computer assisted approach)

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researchers in the fields of formal methods and computer-checked mathematics

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