Question 865155
(0,1)(4,2)(3,6)(-5,4)
(0,1)(4,2)(3,6) forms  right angle
(4,2)(3,6)  y = 18-4 x
(0,1)(4,2) y = x/4+1
slopes are -4 and 1/4 
-4*1/4=-1 they are perpendicular and form a right angle
(4,2)(3,6)(-5,4) forms  right angle
(3,6)(-5,4) y = x/4+21/4
(4,2)(3,6)  y = 18-4 x
slopes are -4 and 1/4 
-4*1/4=-1 they are perpendicular and form a right angle
area 25.5