Answer:
E
Step-by-step explanation:
The problem says that triangle BDC lies in the plane k, which means that whatever angle is formed by another point beyond this plane with any of the three segments that form BDC (BD, DC, and BC) is the same as the angle formed by the line connecting the point and the plane.
Here, we're given that AD⊥DC, which means AD forms a 90° angle with DC. Then, since DC is already on the plane, we already know for sure that AD is definitely perpendicular to plane k.
Thus, the answer is E (none of these).
From the given information, a exists jointly proportional to b and c.
then 
Therefore, the value of a exists 2.
<h3>
What is the value of a?</h3>
Given, a exists jointly proportional to b and c.

Taking K as the constant of proportionality.
a = K b c
For b = 8 and c = 9, the value of a = 4
4 = K(8)(9)
4 = 72 K
Dividing the equation by 72, we get

Using the value of K in the equation:

Substitute the values of b = 2 and c = 18, in the above equation

a = 2
Therefore, the value of a exists 2.
To learn more the value of x refers to:
brainly.com/question/11874663
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Answer:
2
Step-by-step explanation:
Solving is :
X=2
Y=1
Step by step
(2x-3) + 5 = 3x
2x+2=3x
X=2
Substitute x by 2
Y=1
Answer:
Quadrilateral ABCD is inscribed in a circle, then
A + C = 180
=> 2x + 9 + 3x + 1 = 180
=> 5x = 170
=> x = 34
=> A = 2 x 34 + 9 = 77 deg
Hope this helps!
:)