75.8k views
4 votes
A quadrilateral has vertices A= (0,0), B (4,3), C = (1,7) and D= (-3,4)

Prove that ABCD is a parallelogram

Find the area and perimeter of this quadrilateral

A quadrilateral has vertices A= (0,0), B (4,3), C = (1,7) and D= (-3,4) Prove that-example-1
User Comencau
by
7.6k points

1 Answer

3 votes
To prove that ABCD is a parallelogram, we need to show that both pairs of opposite sides are parallel.

First, let's find the slopes of the line segments AB, BC, CD, and DA.

The slope of AB = (y2 - y1) / (x2 - x1) = (3 - 0) / (4 - 0) = 3/4.
The slope of BC = (y2 - y1) / (x2 - x1) = (7 - 3) / (1 - 4) = 4/(-3) = -4/3.
The slope of CD = (y2 - y1) / (x2 - x1) = (4 - 7) / (-3 - 1) = -3/(-4) = 3/4.
The slope of DA = (y2 - y1) / (x2 - x1) = (0 - 4) / (0 - (-3)) = -4/3.

We can see that the slopes of AB and CD are equal (3/4), and the slopes of BC and DA are equal (-4/3). Therefore, both pairs of opposite sides are parallel, and we have proven that ABCD is a parallelogram.

To find the area of the quadrilateral, we can divide it into two triangles: ABC and CDA. The area of a triangle can be calculated using the Shoelace Formula or by applying the formula: Area = (1/2) * base * height.

For triangle ABC:
Base = distance between A and B = √[(4 - 0)^2 + (3 - 0)^2] = √(16 + 9) = √25 = 5
Height = distance between A and C = √[(1 - 0)^2 + (7 - 0)^2] = √(1 + 49) = √50 = 5√2
Area(ABC) = (1/2) * 5 * 5√2 = 25√2

For triangle CDA:
Base = distance between C and D = √[(1 - (-3))^2 + (7 - 4)^2] = √(16 + 9) = √25 = 5
Height = distance between C and A = √[(0 - 1)^2 + (0 - 7)^2] = √(1 + 49) = √50 = 5√2
Area(CDA) = (1/2) * 5 * 5√2 = 25√2

The total area of the quadrilateral ABCD = Area(ABC) + Area(CDA) = 25√2 + 25√2 = 50√2

To find the perimeter of the quadrilateral, we need to calculate the sum of the lengths of all four sides.

AB = √[(4 - 0)^2 + (3 - 0)^2] = √(16 + 9) = √25 = 5
BC = √[(1 - 4)^2 + (7 - 3)^2] = √(9 + 16) = √25 = 5
CD = √[(-3 - 1)^2 + (4 - 7)^2] = √(16 + 9) = √25 = 5
DA = √[(0 - (-3))^2 + (0 - 4)^2] = √(9 + 16)
User Allan Mermod
by
8.8k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories