SOLUTION: Find the measure of all angles of a triangle 12cm, 11cm, 13cm

Algebra ->  Triangles -> SOLUTION: Find the measure of all angles of a triangle 12cm, 11cm, 13cm      Log On


   

Question 448403: Find the measure of all angles of a triangle 12cm, 11cm, 13cm
Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
Use the law of cosines. For example,



, then use your calculator to evaluate the inverse cosine of 4/11 (note to choose a reasonable angle, most probably the acute angle). Repeat the same for the other sides. Keep in mind that you only need to evaluate two of the angles, then subtract the sum of those two from 180 degrees to find the third.