A quadrilateral has vertices at $(0,1)$, $(3,4)$, $(4,3)$ and $(3,0)$. Its perimeter can be expressed in the form $a\sqrt2+b\sqrt{10}$ with $a$ and $b$ integers. What is the sum of $a$ and $b$?

Respuesta :

Answer:

a + b = 12

Step-by-step explanation:

Given

Quadrilateral;

Vertices of (0,1), (3,4) (4,3) and (3,0)

[tex]Perimeter = a\sqrt{2} + b\sqrt{10}[/tex]

Required

[tex]a + b[/tex]

Let the vertices be represented with A,B,C,D such as

A = (0,1); B = (3,4); C = (4,3) and D = (3,0)

To calculate the actual perimeter, we need to first calculate the distance between the points;

Such that:

AB represents distance between point A and B

BC represents distance between point B and C

CD represents distance between point C and D

DA represents distance between point D and A

Calculating AB

Here, we consider A = (0,1); B = (3,4);

Distance is calculated as;

[tex]Distance = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}[/tex]

[tex](x_1,y_1) = A(0,1)[/tex]

[tex](x_2,y_2) = B(3,4)[/tex]

Substitute these values in the formula above

[tex]Distance = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}[/tex]

[tex]AB = \sqrt{(0 - 3)^2 + (1 - 4)^2}[/tex]

[tex]AB = \sqrt{( - 3)^2 + (-3)^2}[/tex]

[tex]AB = \sqrt{9+ 9}[/tex]

[tex]AB = \sqrt{18}[/tex]

[tex]AB = \sqrt{9*2}[/tex]

[tex]AB = \sqrt{9}*\sqrt{2}[/tex]

[tex]AB = 3\sqrt{2}[/tex]

Calculating BC

Here, we consider B = (3,4); C = (4,3)

Here,

[tex](x_1,y_1) = B (3,4)[/tex]

[tex](x_2,y_2) = C(4,3)[/tex]

Substitute these values in the formula above

[tex]Distance = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}[/tex]

[tex]BC = \sqrt{(3 - 4)^2 + (4 - 3)^2}[/tex]

[tex]BC = \sqrt{(-1)^2 + (1)^2}[/tex]

[tex]BC = \sqrt{1 + 1}[/tex]

[tex]BC = \sqrt{2}[/tex]

Calculating CD

Here, we consider C = (4,3); D = (3,0)

Here,

[tex](x_1,y_1) = C(4,3)[/tex]

[tex](x_2,y_2) = D (3,0)[/tex]

Substitute these values in the formula above

[tex]Distance = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}[/tex]

[tex]CD = \sqrt{(4 - 3)^2 + (3 - 0)^2}[/tex]

[tex]CD = \sqrt{(1)^2 + (3)^2}[/tex]

[tex]CD = \sqrt{1 + 9}[/tex]

[tex]CD = \sqrt{10}[/tex]

Lastly;

Calculating DA

Here, we consider C = (4,3); D = (3,0)

Here,

[tex](x_1,y_1) = D (3,0)[/tex]

[tex](x_2,y_2) = A (0,1)[/tex]

Substitute these values in the formula above

[tex]Distance = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}[/tex]

[tex]DA = \sqrt{(3 - 0)^2 + (0 - 1)^2}[/tex]

[tex]DA = \sqrt{(3)^2 + (- 1)^2}[/tex]

[tex]DA = \sqrt{9 + 1}[/tex]

[tex]DA = \sqrt{10}[/tex]

The addition of the values of distances AB, BC, CD and DA gives the perimeter of the quadrilateral

[tex]Perimeter = 3\sqrt{2} + \sqrt{2} + \sqrt{10} + \sqrt{10}[/tex]

[tex]Perimeter = 4\sqrt{2} + 2\sqrt{10}[/tex]

Recall that

[tex]Perimeter = a\sqrt{2} + b\sqrt{10}[/tex]

This implies that

[tex]a\sqrt{2} + b\sqrt{10} = 4\sqrt{2} + 2\sqrt{10}[/tex]

By comparison

[tex]a\sqrt{2} = 4\sqrt{2}[/tex]

Divide both sides by [tex]\sqrt{2}[/tex]

[tex]a = 4[/tex]

By comparison

[tex]b\sqrt{10} = 2\sqrt{10}[/tex]

Divide both sides by [tex]\sqrt{10}[/tex]

[tex]b = 2[/tex]

Hence,

a + b = 2 + 10

a + b = 12

Answer:

a+b=6

Step-by-step explanation:

The tutor verified answer is mostly correct however, if you look under both by comperision sections you will see that it is:

[tex]4\sqrt{2}[/tex] and [tex]2\sqrt{10}[/tex] thus the answer is 4+2=6