In this blog i will go over section 9-4. this section is the law of cosines. this section isnt very hard at all. you just have to plug into the formula and make sure you didnt make a mistake on your calculator or you wont get an anser.
* Law of Cosines is used when you dont have a pair in a non right triangle.
formula: (opp leg) squared =(adj leg)squared +(adj leg) squared-2(adj leg)(adj leg) cos(angle b/w)
examples:
1. Supposed that two sides of a triangle have lengths 3cm and 7cm and that the angle b/w them measures 130 degrees. find the third side.
draw a triangle and label it according to what they told you.
then you just plug the number into the formula.
(p)squared= (3)squared+(7)squared-2(3)(7) cos(130degrees)
then you square root everything
p= square root of 3squared +7squared- 2(3)(7) cos(130) degrees
your answer should be:
p=9.22 cmsquared
That is what i learned from section 9-4. its not hard but you just have to learn the formula and you will be fine.
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