The value could be rewritten as 2(x+4)
c^2 = a^2 + b^2 - 2(ab)(cos C)
c^2 + 2(ab)(cos C) = a^2 + b^2
2(ab)(cos C) = a^2 + b^2 - c^2
cos C = (a^2 + b^2 - c^2) / 2ab - Answer choice E
Hope this helps! :)
To get this you substitute 7 for the x.
7/8(7)-1/2
49/8-1/2
49/8-4/8
45/8 is the value.
Traiangle ABE = triangle CBD this is wrote right
bc. to angle A corespond angle C
and to angle B corespond angle B
and to angle E corespond angle D
so and than you check this posted image these coresponding angles are congruent angles what mean that these two triangles are congruent
