Area of a triangle is A= 1/2 b x h and Area of a parallelogram is A=b x h. So I would say the area of a triangle is half of the area of a parallelogram. Or a parallelogram is double the area of a triangle.
In order to find the angle θ, in <u>radians</u>, whose<u> tangent</u> is
you have to follow those steps
Step 1
Using a<u> calculator</u>
Find the angle θ

Remember that
the angle θ belong to the second quadrant
so
Angle θ=
Step 2
Convert degrees to <u>radians</u>
we know that


therefore
the answer is
the angle θ is 
Isolate the variable by subtracting the 10 from Both sides...
You are then left with
2x=10
Then divide both sides by 2 (to isolate the variable)
Therefore
X=5