Doms blog

Section 9-4. which is the law of cosines.
Law of Cosines formula: (opp leg) squared =(adj leg)squared +(adj leg) squared-2(adj leg)(adj leg) cos(angle b/w)
and law of cosines is only used with isosceles triangles.

Ex: Supposed that two sides of a triangle have lengths 3cm and 7cm and that the angle b/w them measures 130 degrees. find the third side.

(p)squared= (3)squared+(7)squared-2(3)(7) cos(130degrees)
p= square root of 3squared +7squared- 2(3)(7) cos(130) degrees
p=9.22 cmsquared