Answer:
A
Step-by-step explanation:
Perpendicular bisector of a line divides the line into 2 equal parts and it is perpendicular to the line.
First let's find the midpoint of CD. The point is where the perpendicular bisector will cut through the line.
midpoint= 
Thus, midpoint of CD

Gradient of line CD

The product of the gradients of perpendicular lines is -1.
gradient if perpendicular bisector(1)= -1
gradient of perpendicular bisector= -1
y=mx +c, where m is the gradient and c is the y-intercept.
y= -x +c
Subst a coordinate to find c.
<em>Since the perpendicular bisector passes through the point (8, -10):</em>
When x=8, y= -10,
-10= -8 +c
c= -10 +8
c= -2
Thus, the equation of the perpendicular bisector is y= -x -2.
Y - 1 = 4y - 2/3. Move the ys over to one side, +4y crosses over to become -4y,
and -1 crosses over the right side to become +1.
y -4y = -2/3 + 1
-3y = 1 - 2/3
-3y = 1/3 Divide both sides by -3.
-3y/-3 = (1/3) / -3.
y = 1/3 * -1/3
y = - 1/9
The line should equal 180 degrees, so we would subtract 122 from 180 to get 58 degrees. Since the triangle is equilateral, each angle is the same measure, so I believe m<1 should be 58 degrees.