Solve the triangle. a=1.3cm b=2.7cm c=4.2cm. I know the answer I just dont know how to get it???

Question

sgayton27 · Answer

do I use the law of cosines? I've tried but cant seem to get the right answers!

ddcamp · Answer

Yes, law of cosines, at least for the first angle. It may be faster to use law of sines after that.

sgayton27 · Answer

i keep getting domain error

anonymous · Answer

it would be a miracle if this were a triangle

anonymous · Answer

a=1.3cm b=2.7cm c=4.2cm
since $1.3+2.7=4$ the sides don't reach

raden · Answer

1.3 + 2.7 < 4.2  (it is not a triangle)

anonymous · Answer

i.e. you cannot have a triangle with the sum of the lengths of any two sides smaller than the third side

sgayton27 · Answer

that makes sense then why i cant get the right answer. At least i know to use law of cosines. thank you everyone.

anonymous · Answer

yw

anonymous · Answer

if you try it you will see that you are trying to take the inverse cosine of a number that is larger than 1, which is why there is a "domain error"