The terms "sine," "cosine," and "tangent" all refer to various ratios between the angles and/or sides of a right triangle. In a right triangle, the sine of an angle is defined as the length of the side opposite the angle divided by the hypotenuse of the triangle. The abbreviation for sine found in equations and on calculators is sin. Even a basic scientific calculator will have a sine function. Look for a key marked sin. To find the sine of angle, you will usually press the sin key and then enter the angle measurement in degrees. On some calculators, however, you must enter the degree measurement first and then the sin key. You will have to experiment with your calculator or check the manual to find out which it is. To find the sine of an 80 degree angle, you will either need to key in sin 80 followed by the equal sign or enter key, or 80 sin. (The answer is -0.9939.) You can also type in "sine calculator" into a web search, and find a number of easy-to-use calculators that will remove any guesswork. The Law of Sines is a useful tool for solving triangles. In particular, it can help you find the hypotenuse of a right triangle if you know the length of one side, and the measure of one other angle in addition to the right angle. For any triangle with sides a, b, and c, and angles A, B, and C, the Law of Sines states that a / sin A = b / sin B = c / sin C. The Law of Sines can actually be used to solve any triangle, but only a right triangle will have a hypotenuse. The hypotenuse (longest side) must be "c". For the sake of simplicity, label the side with the known length as "a," and the other "b". Then assign variables A, B, and C to the angles of the triangle. The right angle opposite the hypotenuse will be "C". The angle opposite side "a" is angle "A," and the angle opposite side "b" is "B". Because it is a right angle, you already know that C = 90 degrees, and you also know the measure of A or B. Since the internal degree measurement of a triangle must always equal 180 degrees, you can easily calculate the measurement of the third angle using the following formula: 180 (90 + A) = B. You can also reverse the equation such that 180 (90 + B) = A. For example, if you know that A = 40 degrees, then B = 180 (90 + 40). Simplify this to B = 180 130, and you can quickly determine that B = 50 degrees. At this point, you should know the degree measurements of all three angles, and the length of side a. It is now time to plug this information into the Law of Sines equation to determine the lengths of the other two sides. To continue our example, let's say that the length of side a = 10. Angle C = 90 degrees, angle A = 40 degrees, and angle B = 50 degrees. We just need to plug our numbers in and solve the following equation to determine the length of hypotenuse c: length of side a / sin A = length of side c / sin C. This might still look a bit intimidating, but the sine of 90 degrees is a constant, and always equals 1! Our equation can thus be simplified to: a / sin A = c / 1, or just a / sin A = c. You can do this in two separate steps, by first calculating sin A and writing it down, and then dividing by a. Or you can key it all into the calculator at the same time. If you do, remember to include parentheses after the division sign. For example, key in either 10 / (sin 40) or 10 / (40 sin), depending on your calculator. Using our example, we find that sin 40 = 0.64278761. To find the value of c, we simply divide the length of a by this number, and learn that 10 / 0.64278761 = 15.6, the length of our hypotenuse!
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One-sentence summary -- Understand what "Sine" means. Learn to calculate sine. Learn the Law of Sines. Assign the variables a, b, and c to the sides of your triangle. Calculate the measurement of the third angle. Examine your triangle. Apply the Law of Sines to your triangle. Divide the length of side a by the sine of angle A to find the length of the hypotenuse!

Article: If you feel you made a painful mistake by having the relationship, allow the pain to stop you from making the same mistake in the future. There are reasons for certain rules in life. Following them will steer you toward pleasure and away from pain. Follow this simple yet profound principle to ensure a bright future. Relying on yourself will help you cope with the dissolution of a relationship. You know what makes you happy, so participate in activities that increase positive feelings. Psychologists and Psychiatrists are available in your local area and can be located through the American Psychological Association and the American Psychiatric Association.. You are here to live life and enjoy it. Standing up for yourself will remind you that you deserve to be happy, and the world will notice. When you reach a level of healing after a bad experience, other people perceive a positive change. You sent up a flare to signal that you are ready for good things to happen. People might say things like, "Did you do something different? You look great." Your response can be, "Thank you. Yes, I decided to be happy and it is working for me."
Question: What is a summary of what this article is about?
Learn from your mistakes. Be self-reliant in your coping strategies. Seek professional help to identify the behaviors you would like to change if you are struggling with doing it yourself. Stand up for yourself and the life you want.