Question

given a triangle with b=4, c=10, and A=84 degrees, what is the length of a?
a. 14.1
b. 10.4
c. 12.5
d. 13.7

Answer 1

hmmm have you cover the Law of Cosines yet?

Answer 2

Yes @jdoe0001

Answer 3

then is pretty much just a matter of plug and chug =)

\(\bf \textit{Law of Cosines}=a^2=b^+c^2-2bc\cdot cos(A)\\ \quad \\
c=\sqrt{a^2=b^+c^2-2bc\cdot cos(A)}\)

Answer 4

wops, darn. so much for my paste =)

Answer 5

\(\bf \textit{Law of Cosines}=a^2=b^2+c^2-2bc\cdot cos(A)\\ \quad \\
a=\sqrt{b^2+c^2-2bc\cdot cos(A)}\)

Answer 6

i dont know what a is tho..

Answer 7

yes, but you do you know the other factors, "b" and "c" and angle A

Answer 8

ya ok. let me figure it out and ill come back to ya

Answer 9

ok

Answer 10

i got b @jdoe0001

Answer 11

yeap

Answer 12

\(\bf a=\sqrt{4^2+10^2-2(4)(10)\cdot cos(84^o)} \approx 10.374860140\)