Answer:
option 3
Explanation:
calculate the slopes using the slope formula
m =

with (x₁, y₁ ) = E (1, 2 ) and (x₂, y₂ ) = F (6, 12 )
=
=
= 2
repeat with (x₁, y₁ ) = R (12, 17 ) and (x₂, y₂ ) = T (32, 7 )
=
=
= -

If perpendicular then the product of their slopes equals - 1
×
= 2 × -
= - 1
Yes, the lines are perpendicular because the product of their slopes equal - 1
(2)
E (3, 7 ) and F (13, 17 )
=
=
= 1
R (4, 9 ) and T (8, 5 )
=
=
= - 1
×
= 1 × - 1 = - 1
yes, the lines are perpendicular because the product of their slopes equal - 1
(3)
(- 20, 5 ) and (- 4, 7 )
m =
=
=
=

(- 5, 5 ) and (7, 4 )
m =
=
= -

× -
≠ - 1
No, the lines are not perpendicular because the product of their slopes does not equal - 1