What is the measure of angle 4?

Mathematics

1 answer:

myrzilka [38]2 years ago

3 0

There’s a couple actually, I think u forgot to post the picture to show the problem

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A triangle is dilated by a scale factor of 1/5 and then rotated 90 degree clockwise about the origin. Why is the image similar t

yan [13]

Answers:
The corresponding angles of the triangles are congruent
The image is a reduction of the pre-image
Neither the dilation nor the rotation change the shape of the triangle

Explanation:
For shapes to be similar:
1- there should be a ratio between the sides
2- angles in first shape should be congruent to angles in second shape

Now, a scale factor of 0.2 means that the sides of the image are 0.2 of the length of the original shape. However, angles are not changes

Let's check the choices:
1- The corresponding sides of the triangles are congruent:
This option is incorrect as dilation changes the lengths of the sides

2- The corresponding angles of the triangles are congruent:
This option is correct as neither dilation nor rotation alters the measures of the angles

3- The corresponding sides of the image are 5 times as long as those of the pre-image:
This option is incorrect as the sides of the image are only 0.2 times as long as those of the pre-image

4- The image is a reduction of the pre-image:
This option is correct as the sides of the image are 0.2 times those of the pre-image which means that the shape is reduced

5- Neither the dilation nor the rotation change the shape of the triangle:
This option is correct as both dilation and rotation are rigid transformations that do not alter the shape of the triangle (a triangle remains a triangle only with different side lengths)

6- The rotation reduces the size of the triangle:
This option is incorrect as rotation does not alter the size of the shape. It only changes its position

Hope this helps :)

3 0

3 years ago

Read 2 more answers

#2 is the one I need help with

sleet_krkn [62]

Step-by-step explanation:

By arc sum Postulate of a circle:

2 x + 3x + 4x = 360°

9x = 360°

x = 360°/9

x = 40°

3x = 3* 40° = 120°

By inscribed angle theorem:

$m\angle 1= \frac {1}{2} \times 3x\\\\\therefore m\angle 1= \frac {1}{2} \times 120°\\\\\huge \red {\boxed {\therefore m\angle 1= 60°}}$

By tangent secant theorem:

$m\angle 2 = \frac {1}{2} \times 3x\\\\\therefore m\angle 2 = \frac {1}{2} \times 120°\\\\\huge \purple {\boxed {\therefore m\angle 2 = 60°}}$

Since, measure of central angle is equal to the measure of its corresponding minor arc.

$m\angle 3 = 3x\\\\\huge \pink {\boxed {\therefore m\angle 3 = 120°}}$

By angle sum Postulate of a triangle:

$m\angle 3 + 2 m\angle 4 = 180°\\\\120° + 2 m\angle 4 = 180° \\\\2 m\angle 4 = 180°- 120° \\\\2 m\angle 4 = 60° \\\\m\angle 4 = \frac {60°}{2} \\\\\huge \orange {\boxed {m\angle 4 =30°}}$