How can I find the two smaller angles in a triangle with sides of 7 in., 7 in., and 13 in.?

Question

I would like to know the steps of how to get the answer to my question, I don't want just the answer, because I want to be able to also do it on my own in the future. My problem can be solved by using the Law of Cosines. Thank you for whoever is able to answer my question, much appreciated :)

Answer 1

Yes, you may use The Cosine Law.  Let's say AB=BC=7, AC=13 By the law: 13^2=7^2+7^2- 2x7x7 cos B

169=98-98cosB

cosB=-0.7245

m<B=136.4 degrees

So the smaller angles will be (180-136.4):2=21.3 degrees each

Answer 2

How can I find the two smaller angles in a triangle with sides of 7 in., 7 in., and 13 in.?

draw the triangle first.  I can't because this won't let me.  remember this is an isosceles triangle, that means that two sides and angles are the same.  Is it a right angle?  if it is that means that it has a 90 degree and 2 - 45 degree angles.

Comments

no, it is not a right triangle( 7^2 + 7^2 does not =13^2)