68Answer:
10
Step-by-step explanation:
68/2=34
24+10=34
20
Step-by-step explanation:
Step 1:
Let the number be 50 and to find 40% of 50 is given interms of expression as follows
To express the percentage the following strategy is used
Eg: 40% = 
∴ To express 40% of 50 is

Step 2:
On simplification the above expression we could get

= 20
I believe the answer is 0, but I could be wrong!
Answer:
55 degrees
I answered the question on AoPS and it said it was correct.
Answer:
Step-by-step explanation:
Vertices of the given quadrilateral are A(-4, 3), B(2, -1), C(2, -5) and D(-4, -1)
Since, slope of a line passing through two points
and
is given by,
Slope = 
Slope of AB = 
= 
Slope of AD = 
= Not defined (Parallel to y-axis)
Slope of DC = 
= 
Slope of BC = 
= Not defined (Parallel to y-axis)
Slope of AB = slope of DC = 
Slope of BC = slope of AD = Not defined (parallel to y-axis)
As per property of a parallelogram,
"Opposite sides of a parallelogram are parallel and equal in measure"
Therefore, ABCD is a parallelogram.