I got the stuff down cold but I cant seem to figure out this problem
Side 1=7.21
Side 2=7.21
Side 3=10
The question states: Using law of sines or law of cosines find all 3 angles.
Its so easy but i keep blanking.
I got the stuff down cold but I cant seem to figure out this problem
Side 1=7.21
Side 2=7.21
Side 3=10
The question states: Using law of sines or law of cosines find all 3 angles.
Its so easy but i keep blanking.
I changed 1,2 and 3 to a,b and c respectively to make notation easier. In a triangle side a is opposite angle A and so on.
Use the cos rule to find angle C:
$\displaystyle cos(C)=\frac{a^2+b^2-c^2}{2ab}$
Then you can use the sine rule rule to find A and/or B:
$\displaystyle \frac{a}{sin(A)} = \frac{b}{sin(B)} = \frac{c}{sin(C)}$
To find the last angle either use the sine rule again or (easier) take the other two angles from pi or 180 degrees
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edit: Since this is an isosceles triangle side a = side b and so angle A = angle B
Once you've found angle C you can do $\displaystyle \frac{\pi - C}{2}$