determine area of triangle. A=112 degrees
b=7, and c=11

Question

determine area of triangle. A=112 degrees 
b=7, and c=11

dumbcow · Answer

|dw:1369681707774:dw|
ok use Law of cosines to find side "a"
then Law of Sines to find angle "C"

then find height of triangle
--> sinC = height/7

then find Area
--> Area = 1/2*height*"a"

dumbcow · Answer

there may be a faster method or formula im not remembering

anonymous · Answer

how do you find the angles though?

dumbcow · Answer

$$a^{2} = 7^{2}+11^{2}-2(7)(11)\cos 112$$
and
$$\frac{\sin C}{11} = \frac{\sin 112}{a}$$

anonymous · Answer

|dw:1369681976026:dw|
CD is the height and is 7 times the sin 68.  Then :

A = (1/2)bh

where AB is the base.

dumbcow · Answer

see a faster method

anonymous · Answer

thanks, guys!

anonymous · Answer

uw!

mertsj · Answer

Just use the formula :
$$A=\frac{1}{2}ab \sin C=\frac{1}{2}(7)(11)\sin 112$$

mertsj · Answer

A=35.7

anonymous · Answer

yes, Mertsj's way will also give the same answer because sin 112 = sin 68

dumbcow · Answer

@BeautyQueen327 , you now have 2 methods, a formula and how that formula is derived
i think you should now thoroughly understand how to do this problem :)

anonymous · Answer

i do! Dont worry! :P I said earlier, thanks, guys! But no one saw it i guess...