Sine, Cosine, and Tangent Rules

Sine (sin), Cosine (cos), Tangent (tan) are functions that express the ratio of the sides or angle degrees of a rigt triangle, and the right triangle's sides are classified into Hypotenuse ( the side looking at the right angle ), Opposite ( the side facing or opposite to the angle given in the problem " θ " ), Adjacent ( the angle beside the angle given in the problem " θ " ) and that angle is called " θ " Sita; Now to find the ratios of the sides; if you look at the image above, to find the sin you get the Opposite over the Hypotenuse, to find cos you get the Adjacent over the Hypotenuse, and to find tan you get the Opposite over the Adjacent (All of this is answered through using a Calculator). On how to get a missing side you look at the right triangle and see which rule you are going to use (sin, cos, tan) and use multiply the given side (There will always be a given side) and multiply it with the Sin, Cos, or Tan of the angle given. On how to get the missing angle, there will be 2 given sides, see which is going to be used and then press shift on your Calculator and then the rule's name, then enter the fraction of the 2 sides (depends on the rule) and press equal, and you get your answer.

Lets look at the image above with the green right trinagle, to find the sin get the Opposite side over the Hypotenuse and that is the it in Fraction Form (keep it as a Fraction), and the same goes for the Cos and Tan. As for the second image, we look at the rule needed and it seems to be Cos, so it will be cos28 = x / 15, after cross multiplication to keep X alone, so it will be x = 15(cos28) after it is written in your Calculator, press equal and the answer ( Round to the nearst tenth ) is x = 13.2.

Notes: Memorize the Rules and their Values.
When there is an angle or side missing, keep the x alone to avoid confusion.