This will plot something like figure 1 without the annotation.
%Define First line, each column is a point, first row is x, second row is y
len = 1;
line1 = [0 len; 0 0];
%Define angle and rotation matrix to calculate x and y together
angle = pi/2/4;
rotMatrix = [cos(angle) -sin(angle); sin(angle) cos(angle)];
line2 = rotMatrix*line1;
line3 = rotMatrix*line2;
%Plot the lines, splitting each row into x and y
%Define and plot the arc
a = 0:angle/100:angle*2;
%Set the limits on the X and Y for looks
Is that what you're looking for?