Question

Rectangle KLMN has vertices K(-5,6), L(-2,9), M(6, 1), and N(3,-2). Determine and state the coordinates of the point of intersection of the diagonals.

Answer 1

Answer:

(0.5,3.5)

Step-by-step explanation:

First, we can draw the image, as shown. The diagonals in the rectangle are the following lines:

from (-2,9) to (3,-2)

from (-5, 6) to (6,1)

To find where they intersect, we can start by making an equation for the lines. For an equation y=mx+b, m represents the slope and b represents the y intercept, or when x=0

For the first line, from (-2,9) to (3,-2), we can calculate the slope by calculating the change in y/change in x = (y₂-y₁)/(x₂-x₁). If (3,-2) is (x₂,y₂) and (-2,9) is (x₁,y₁), our slope is

(-2-9)/(3-(-2)) = -11/5

Therefore, our equation is

y= (-11/5)x + b

To solve for b, we can plug a point in, like (3,-2). Therefore,

-2=(-11/5)*3+b

-2=-33/5+b

-10/5=-33/5+b

add 33/5 to both sides to isolate b

23/5=b

Our equation for one diagonal is therefore y=(-11/5)x+23/5

For the second line, from (-5, 6) to (6,1), if (6,1) is (x₁,y₁) and (-5,6) is (x₂,y₂), the slope is (1-6)/(6-(-5)) = -5/11 . Plugging (6,1) into the equation y=(-5/11)x+b, we have

1=(-5/11)*6+b

11/11 = -30/11 + b

add 30/11 to both sides to isolate b

41/11 = b

our equation is

y = (-5/11) x + 41/11

Our two equations are thus

y = (-5/11) x + 41/11

y=(-11/5)x+23/5

To find where they intersect, we can set them equal to each other

(-11/5)x+23/5 = y = (-5/11) x + 41/11

(-11/5)x + 23/5 = (-5/11)x + 41/11

subtract 23/5 from both sides as well as add 5/11 to both sides to make one side have only x values and their coefficients

(-11/5)x + (5/11)x = 41/11-23/5

11*5 = 55, so 55 is one value we can use to make the denominators equal.

(-11*11/5*11)x+(5*5/11*5)x=(41*5/11*5)-(23*11/5*11)

(-121/55)x+(25/55)x = (205/55) - (253/55)

(-96/55)x = (-48/55)

multiply both sides by 55 to remove the denominators

-96x=-48

divide both sides by -96 to isolate x

x=-48/-96=0.5

plug x=0.5 into a diagonal to see the y value of the intersection

(-11/5)x + 23/5 = y = (-11/5)* 0.5 + 23/5 = 3.5