Answer:
Option D. 
Step-by-step explanation:
step 1
Find the midpoint of the given line segment
we know that
The formula to calculate the midpoint between two points is equal to
we have

substitute the values
step 2
Find the equation of the perpendicular bisector
we know that
The equation of a perpendicular bisector is equal to the x-coordinate of the midpoint, because is a vertical line (parallel to the y-axis)
therefore
the equation is equal to

a+b+c=0
[(a+b+c)^2=a^2+b^2+c^2+2ab+2ac+2bc]
[a^2+b^2+c^2+2ab+2ac+2bc=0]
[a^2+b^2+c^2=-(2ab+2ac+2bc)]
[a^2+b^2+c^2=-2(ab+ac+bc)] (i)
also
[a=-b-c]
[a^2=-ab-ac] (ii)
[-c=a+b]
[-bc=ab+b^2] (iii)
adding (ii) and (iii) ,we have
[a^2-bc=b^2-ac] (iv)
devide (i) by (iv)
[(a^2+b^2+c^2)/(a^2-bc)=(-2(ab+bc+ca))/(b^2-ac)]
Hi there!
We know that RST is an equilateral(all 3 sides the same length) triangle, and is therefore equiangular(all 3 angles the same value). Therefore, angle S and is equal to one-third of the triangle's angle measure.
180/3=60
60=7x+4
56=7x
x=8
-AwesomeRepublic :)
You can just use a calculator but when you add the numbers all together you get 323
5 students scored a 90 or above. If you look at the axis that says “test scores” just count the number of dots on the “90” line and above