Become a member. Together, CAP and ADID are committed to a Downtown that is a thriving city center for the diverse Atlanta community including Downtownâs property owners, employees, residents, students and visitors.
In the last lesson we used the Law of Cosines to find the length of the third side of a triangle when you know the length of two sides and the angle in between. This law can also be used to find the measure of an angle when the three sides of a triangle are given. To use the Law of Cosines to find an unknown angle: 1. Identify c as the side across from the angle you are trying to find. 2. Substitute the values into the Law of Cosines.
From one of the vertices drop a perpendicular to the opposite side dividing that side in two lengths each of length 1 unit. The perpendicular is of length sqrt{2^2 - 1^2} = sqrt{4-1} = sqrt{3} The perpendicular bisector divides the 60 degree angle into two equal angles each of 30 degrees.We now have a triangle of 30, 60, 90 degrees with corresponding opposite sides of 1 unit, sqrt{3} units, 2 units respectively.he hypotenuse will in such a case be sqrt{1^2 + 1^2} = sqrt{1+1} = sqrt{2}. Sine(45) = Opposite Side/Hypotenuse = 1/[sqrt(2)] Cosine(45) = Adjacent Side/Hypotenuse = 1/[sqrt(2)] Tangent(45) = Opposite Side/Hypotenuse = 1/1 = 1 As regards the 30 and 60 degrees: Consider an equilateral triangle of side 2 unit each side.