2 methods ...
1. find the length of each of the sides, then used the cosine law to find the largest angle,
then use the sine law to find a second angle.
Once you have 2 angles, use the supplementary angle theorem to find the 3rd
2. find vectors AB and AC, then use the dot product to find angle A
repeat for another angle
Determine the interior angles of triangle ABC for A(5,1), B(4,-7) and C(-1, -8).
1 answer