Answer:
Reference angle will be 30°
sin(330°) will be equal to 
cos(330°) will be equal to 0.866
Step-by-step explanation:
We have given angle is 330°
As the angle
is in forth quadrant
We know that in forth quadrant the reference angle is given by
Reference angle 
As the angle is 330°
So the reference angle will be 
Now we have to find the value of
sin(330°) 
And now 
A trapezoid is isosceles if and only if
(1) The base angles are congruent
(2) The diagonals are congruent
(3) The opposite angles are supplementary
So the description does not guarantee that a trapezoid is isoceles for "Congruent bases".
Answer:
the answer of given question is $400.