Answer:
Given:
and
.
Prove: 
Since
, By the definition of perpendicular lines angles 1, 2, 3 and 4 are 90 degree. similarly
, it means angles 5, 6, 7 and 8 are 90 degree.
We can say that,
,
,
and 
From figure it is noticed that the angle 1 and 5 are corresponding angles.
If two parallel lines are intersected by a transversal, then the corresponding angles are equal.
Since corresponding angles are congruent, therefore the line must be parallel to each other.
Hence proved that
.
Answer:
Mean = 1.57
Variance=0.31
Step-by-step explanation:
To calculate the mean and the variance of the number of successful surgeries (X), we first have to enumerate the possible outcomes:
1) Both surgeries are successful (X=2).

2) Left knee unsuccessful and right knee successful (X=1).

3) Right knee unsuccessful and left knee successful (X=1).

4) Both surgeries are unsuccessful (X=0).

Then, the mean can be calculated as the expected value:

The variance can be calculated as:

8 friends share 3 cookies.
There are 3 cookies and 8 people.
We need to know how much cookie 1 friend gets.
1 friend gets 3/8 of a cookie.
There are 8 friends, so 8 x 3/8 = 3. The 8 friends will finish 3 cookies if they all have 3/8 of a cookie.
Each friend gets 3/8 of a cookie.
Solution:
<em>the</em><em> </em><em>answer</em><em> </em><em>please</em><em> </em><em>mark</em><em> </em><em>as</em><em> </em><em>brainly ness</em><em> </em>
<em>your</em><em> </em><em>welcome</em>
Answer:
maybe it's 10.because c is 10,b is 10,and so as s.
hence s is 10 also.