Problem: Article: The Sine Rule, also called the law of sines, is a rule of trigonometry that relates the sides of a triangle and its angle measurements. While most of trigonometry is based on the relationships of right triangles, the law of sines can apply to any triangle, whether or not it has a right angle.' The law of sines is stated as follows: Asin=Bsin=Csin{\displaystyle {
rac {A}{\sin lpha }}={
rac {B}{\sin eta }}={
rac {C}{\sin \gamma }}} The same rule can be rearranged to yield the following equivalent statements: sinA=sinB=sinC{\displaystyle {
rac {\sin lpha }{A}}={
rac {\sin eta }{B}}={
rac {\sin \gamma }{C}}} For the law of sines to be useful, you must know the measurements of at least two angles and one side, or two sides and one angle. In either case, you must have at least one pair that consists of a side and its opposite angle. For example, the following combinations would be sufficient for the law of sines to apply: Side A, Side B and angle {\displaystyle lpha } Side A, Side C, and angle {\displaystyle \gamma } Side B, angle {\displaystyle eta } and angle {\displaystyle lpha } The following combinations are examples that would NOT be sufficient to apply the law of sines: Side A, Side B and Side C. (This does not work because you have no angle measurement.) Side A, Side B and angle {\displaystyle \gamma }. (This does not work because the known angle is not opposite either of the known sides. Side B, angle {\displaystyle lpha } and angle {\displaystyle \gamma }. (This does not work because the known side is not opposite either of the known angles.) The law of sines works to help you find one piece of information about a triangle -- a side or an angle measurement -- if you know three others. While the full law of sines is written as a three-part equation, you only need to equate two for the rule to work. For example, if you know sides A and B and angle {\displaystyle lpha }, then you need the portion of the law of sines that says: Asin=Bsin{\displaystyle {
rac {A}{\sin lpha }}={
rac {B}{\sin eta }}} Notice the similarity of the law. It really doesn't matter which label you use for any sides or angles. The important thing to remember is that you are comparing ratios. The ratio of any side to its opposing angle is equal to the ratio of any other side to its opposing angle. Suppose you are given that side A is 12, angle {\displaystyle lpha } is 80 degrees, and angle {\displaystyle eta } is 40 degrees. Find the length of side B. You can mark these numbers on the triangle and set up the problem as follows: Asin=Bsin{\displaystyle {
rac {A}{\sin lpha }}={
rac {B}{\sin eta }}} 12sin80=Bsin40{\displaystyle {
rac {12}{\sin 80}}={
rac {B}{\sin 40}}} Use basic algebra to maneuver the unknown information to stand alone on either side of the equation. You can then reduce the problem to find the answer. 12sin80=Bsin40{\displaystyle {
rac {12}{\sin 80}}={
rac {B}{\sin 40}}} 12sin40sin80=B{\displaystyle {
rac {12\sin 40}{\sin 80}}=B} 7.83=B{\displaystyle 7.83=B} To find the value of the sine of an angle, such as sin40{\displaystyle \sin 40} in the problem above, you can use most handheld calculators with trigonometric functions. Different calculators operate differently. With some calculators, you will enter your angle measurement first and then the "sin" button. With others, you will enter the "sin" button first and then the angle measurement. You will have to experiment with your calculator. Alternatively, there are some tables available either in math books or online. With a trigonometry table, you can find your desired angle measure in one column and the corresponding value of sine, cosine or tangent in another column.
Summary: Understand the Sine Rule. Review the data you need. Write the portion of the law of sines that you need. Fill in the numbers that you know. Rearrange to solve for the unknown information.

Problem: Article: Click the Firefox menu and select Add-ons. Select Extensions in the Add-ons window. Click the Remove button next to the entry to remove the MyStart toolbar. Click the Search engine icon next to the Search field in the Firefox window. Select Manage Search Engines from the menu. Click on MyStart Search and click the Remove button. Click the Firefox menu and select Options. Select the General tab. Change the address in the Home Page field to whatever you wish. Enter the address "about:config" into the address bar and press Enter. Confirm that you want to continue and then enter "mystart" into the Search field that appears. This will display a list of preferences that were changed by MyStart. Right-click on each one and select Reset. Click the Firefox menu, hover over History, and select Clear Recent History. In the window that appears, set the time range to Everything, and then make sure that Cookies, Cache, and Browsing History are checked. Click the Clear Now button.
Summary:
Remove the toolbar. Remove the MyStart search engine. Change your home page back. Reset your preferences. Delete your browser data.