To solve a triangle you must be given 3 independent bits of information.
2 sides and 1 angle
3 sides
1 side and 2 angles
(note 3 angles is not "3 independent pieces of information, since if you know 2 angles, you automatically know the third)
general simple rule:
If you are given a side and its opposite angle, use the sine law
if not, use cosine law.
so for yours, clearly sine law.
Should the triangle be solved beginning with Law of Sines of Law of Cosines. Then solve the triangle. Round to the nearest tenth. A=56 degrees, B=38 degrees, a=13.
Sines. I get confused on the formula. I know C=86 degrees
7 answers
I know I need to use the law of sines but I don't really know how and which one to use like sinA/a= sin B/b and sinB/b =sinC/c and sinA/a = sinC/c. That's where I get confused.
clearly you are given a side and its opposite angle, a and A, so that is obviously the ratio you are going to use
SinA/a = SinB/b
sin56/13 = sin38/b crossmultiply and solve for b.
b = 13sin38/sin56
= 9.65
do the same to find c
SinA/a = SinB/b
sin56/13 = sin38/b crossmultiply and solve for b.
b = 13sin38/sin56
= 9.65
do the same to find c
b=9.7(i had to round)
im not sure if im doing this right.
SinB/b = SinC/c
Sin38/9.7 = Sin86/c
c = 9.7sin38/sin86
c= 5.98 or 6 since I have to round to nearest tenth.
im not sure if im doing this right.
SinB/b = SinC/c
Sin38/9.7 = Sin86/c
c = 9.7sin38/sin86
c= 5.98 or 6 since I have to round to nearest tenth.
why would you not stick with the exact ration sin56/13, which uses the original numbers given
You used an answer that you obtained after you rounded off that answer, so you are compounding your error.
You used an answer that you obtained after you rounded off that answer, so you are compounding your error.
so to find c all I have to do is
Sin56/13 = Sin86/c
c = 13Sin56/Sin86
c = 10.8
Sin56/13 = Sin86/c
c = 13Sin56/Sin86
c = 10.8
NO
Sin56/13 = Sin86/c now cross-multiply
csin56 = 13sin86 divide by sin56
c = 13sin86/sin56
c = 15.6
check: in any triangle, your smallest side should be across from the smallest angle, the largest side should be across the largest angle.
Sin56/13 = Sin86/c now cross-multiply
csin56 = 13sin86 divide by sin56
c = 13sin86/sin56
c = 15.6
check: in any triangle, your smallest side should be across from the smallest angle, the largest side should be across the largest angle.