Do tomorrow if not done I will fail

If the value of cos330°is√3/2 then find cos 165°.

Solve these problems: 1.what is the perimeter of an equilateral triangle with sides measuring 6cm? 2. a regular pentagon has sides measuring 3.2 cm. what is its perimeter? 3. a regular decagon has sides of 3.5mm . what is it’s perimeter? 4. a regular octagon has a perimeter of 64cm. what is the length of one of the sides? 5. a regular hexagon has a perimeter of 72mm . what is the length of one of the sides? 6. what is the perimeter of a rhombus with sides measuring 11m?

Bc and bd are opposite rays. all of the following are true except a)a, b,c, d are collinear b)a, b,c, d are coplanar c)bc=bd d)b is between c and d