Parallelogram.
Opposite sides are parallel.
in a rhombus and square all sides are equal so it isn't those.
It isn't a rectangle either because in a rectangle all angles are ninety degrees
So the definition of the cosine of an angle of a right triangle is

. You may remember this by SohCahToa (sine is opposite over hypotenuse, cosine is adjacent over hypotenuse, tangent is opposite over adjacent).
Remember, adjacent refers to the side next to the angle in question, and the side can't also be the hypotenuse. The hypotenuse is that longest side and is opposite the right angle.
We have the cosine of 30°. We write
Answer:
∠abc=34°
∠dbc= 44°
Step-by-step explanation:
(5x+4)+(5x-6)=78
10x-2=78
10x=78+2
10x=80
x=8
put x in each equation
∠abc= 5x8-6
40-6
34°
78-34= ∠dbc
∠dbc= 44°
Expand the square: 4(x-11)^ =25
4(x-11)(x-11)=25
Distribute : 4(x-11)(x-11)=25
4(x(x-11)-11(x-11))=25
Distribute: 4(x(x-11)-11(x-11))=25
4(x^-11x-11(x-11))=25
Solution: x=17/2
x=27/2
hope that helps
Find the ratio of the similar known sides:
1.34/2 = 0.67
The smaller triangle is 0.67 the size of the larger one.
Multiply the similar sides by the ratio:
DE = 4 x 0.67 = 2.68
FE = 3 x 0.67 = 2.01