Quadrilateral ABCD has vertices AC-3.6), B(6,0), C(9. -9), and D(0, -3). Prove that ABCD is a) a parallelogram
1 answer:
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Explanation:
The quadrilateral will be a parallelogram if the diagonals bisect each other. That will be the case if the sums of their end-point coordinates are the same.
A + C = (-3, 6) +(9, -9) = (6, -3)
B + D = (6, 0) +(0, -3) = (6, -3)
Both diagonals have their midpoint at (3, -1.5), so the diagonals are mutual bisectors. The figure ABCD must be a parallelogram.
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The midpoint of AC is (A+C)/2 = (6, -3)/2 = (3, -1.5).
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Answer:
a
Step-by-step explanation:
A perpendicular bisector, intersects a line at its mid point and is perpendicular to it.
Calculate slope m using the slope formula
m =
with (x₁, y₁ ) = (- 7, 1) and (x₂, y₂ ) = (9, 13)
m = =
=
=
Given a line with slope m then the slope of a line perpendicular to it is
= -
= -
= -
← slope of perpendicular bisector
Given endpoints (x₁, y₁ ) and (x₂, y₂ ) then the midpoint is
(,
)
using (x₁, y₁ ) = (- 7, 1) and (x₂, y₂ ) = (9, 13) , then
midpoint = ( ,
) = (
,
) = (1, 7 )
The equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
Here m = - , then
y = - x + c ← is the partial equation
To find c substitute the midpoint (1, 7) into the partial equation
7 = - + c ⇒ c =
+
=
y = - x +
← equation of perpendicular bisector