Question

Graph the image of the given triangle, reflected across the y-axis. Select the Polygon tool. Then, click the points of the triangle vertices to create the triangle by connecting the sides.

Solve for x.



Enter your answer in the box.

Answer 1

First part :

By the given graph,

The vertices of the given triangle ABC ( let ),

A(7, -4), B(-2, -9) and C(9, -7),

∵ The rule of reflection across y-axis,

`(x,y)\rightarrow (-x,y)`

Thus, the vertices of transformed triangle A'B'C' would be,

A'(-7,-4), B'(2, -9) and C'(-9,-7),

By plotting the points in the given graph then joining them we will obtain the image of the given triangle,

( shown below ),

Second Part :

The sum of all interior angles of a hexagon is 720°,

Thus, by the given diagram,

x° + 121° + 108° + 102°+ 100° = 720°,

x° + 431° = 720°

⇒ x° = 720° - 431 = 289°,

Hence, the value of x would be 289

Answer 2

1) We are given a hexagon there.

Sum of all angles of a hexagon is 720.

Therefore, sum of all angles inside pentagon =720.

We can step an equation as

x+100+102+108+121 = 720.

Adding 100+102+108+121, we get 431.

Therefore,

x+431 = 720.

Subtracting 431 from both sides, we get

x+431-431 = 720-431

x=289.

Therefore, measure of unknown angle x= 289 degrees.

2) Coordinates of the vertices of the given triangle

(-2,-9)

(7,-4)

(9,-7).

We need to graph the reflected triangle across the y-axis.

For reflected triangle across the y-axis we can apply rule

(x,y) --> (-x,y)

By applying above rule, we get the coordinates of reflected triangle as

(-2,-9) --> (2,-9)

(7,-4) --> (-7,-4)

(9,-7) --> (-9,-7).

Now, we can plot those coordinates on the graph and join the coordinates to form a triangle.