Question

Find m of angle a if a = 34, b = 28 and c = 15. (Points : 3)

Answer 1

as in a triangle? need law of cosines for this one

Answer 2

yes

Answer 3

you can start with
\[a^2=b^2+c^2-2bc\cos(A)\] and solve for \(\cos(A)\) or go right to
\[\cos(A)=\frac{b^2+c^2-a^2}{2bc}\]

Answer 4

so for angle A you need
\[\cos^{-1}(\frac{b^2+c^2-a^2}{2bc})\]

Answer 5

calculator exercise now

Answer 6

ok ummm can u show me

Answer 7

replace a by 34, b by 28, c by 15

Answer 8

ok what is the cos thing?

Answer 9

inverse cosine or arccosine
here is what i got from wolfram
http://www.wolframalpha.com/input/?i=arccos%28%2824%5E2%2B25%5E2-34%5E2%29%2F%282*15*24%29%29

Answer 10

i am not sure what you are asking. this problem is solved using the law of cosines. so in order to do it you need to know about cosines

Answer 11

ok so the answer is 2.329?

Answer 12

no, check the link i sent

Answer 13

ok what about 67.25?

Answer 14

i put the numbers in incorrectly
try this one
http://www.wolframalpha.com/input/?i=arccos%28%2828%5E2%2B15%5E2-34%5E2%29%2F%282*15*28%29%29

Answer 15

looks like 100.1 degrees from wolfram

Answer 16

ok sweet would 100.08 work?

Answer 17

according to wolfram it is 101.1

Answer 18

ok ok its just a matter of how you round it:)

Answer 19

here is a picture of the triangle
http://www.wolframalpha.com/input/?i=triangle+28%2C+15%2C+34+angles+