we are learning about the law of cosine
the law is used only when you do not have a right triangle or when you can not use law of sine (which i explained in my last blog)
the formula for law of cosine is (opposite leg) squared=(adjacent leg)squared + (adjacent leg)squared-2(adjacent leg)(adjacent leg)cosine(angle between)
example problem
suppose that two side of a triangle have lengths 4 and 8 cm and that angles between them that measures to 120 degrees. find the third side.
first you must draw your triangle so you can have picture of what you are doing.
then you need to solve your problem.
P squared=(4)2+(8)2-2(4)(8)cosine(120)
when you putting your problem in your calculator you need to put whole problem under a square root or you will not get the right answer.
P=10.58
No comments:
Post a Comment