Question

Solve triangle DEF by finding the following sides and angles. Show all work. Round your answer to the nearest tenth.
a)The length of the side opposite angle D.
b)The measure of angle E.
c.The measure of angle F.

Answer 1

law of cosines for this one

Answer 2

if we call the side opposite \(D\) say \(d\) then
\[d^2=17^2+21^2-2\times 17\times 21\cos(68)\]

Answer 3

then take the square root to find \(d\)
i get \(21.5\) rounded
http://www.wolframalpha.com/input/?i=sqrt%2817^2%2B21^2-2*17*21*cos%2868%29%29

Answer 4

then abandon the law of cosines and use the law of sines to find another angle

Answer 5

for example
\[\frac{\sin(E)}{21}=\frac{\sin(68)}{21.5}\] so \[\sin(E)=\frac{21\sin(68)}{21.5}\]

Answer 6

since you want \(E\) and not \(\sin(E)\) take the arcsine of the answer

Answer 7

holy crap

Answer 8

lol

Answer 9

pretty easy with the wolf
http://www.wolframalpha.com/input/?i=arcsin%2821*sin%2868%29%2F21.5%29

Answer 10

so how would you find the angle to angle f

Answer 11

looks like \(E=64.81\)

Answer 12

how do you find the angle \(F\) ?

Answer 13

we got \(D=68,E=64.81\) i bet you can find \(F\)

Answer 14

oh, I got this now. little out of it today. thank you so much