Answer:
3. A quadrilateral with each side length 4 cm
Step-by-step explanation:
We need to understand what is a unique polygon?
<em>It means all regular polygons with the same number of sides are similar.</em>
1.A triangle with angles 30 degrees, 60 degrees, and 90 degrees
It is an right triangle, so the 3 sides are not simillar, so it is wrong
2. A triangle with side lengths 5 cm, 4 cm, and 3 cm
It is a triangle with the 3 sides are not simillar, so it is wrong
3. A quadrilateral with each side length 4 cm
It is an square with the 4 sides are simillar, so it is true
4. A triangle with side lengths 7 cm and 8 cm and a 40-degree angle
It is a triangle with the 3 sides are not simillar, so it is wrong
Hence, we choose 3.
D. (2,3)
Explanation:
We already know that x=2, so of we plug in 2 for x, we should get the y value.
Once we plug in 2 for x we should get the equation:
2(2)+3y=13.
Simplify that and we get:
4+3y=13.
Subtract 4 from both sides and we get:
3y=9.
Divide both sides by 3 and we get:
y=3.
This means that your ordered pair should be (2,3).
Hope this helps :)
Answer: 
Step-by-step explanation:
Given a System of linear equations, the solution of the system is the point
in which the lines intersect, where "x" is the x-coordinate and "y" is the y-coordinate.
Having the following System of equations:

You can use the Elimination method to find the value of "x":
-Multiply the second equation by 3.
- Add the equations.
- Solve for "x".
Then, you get:

Answer:
9 2/3% (or 9.66666666666%)
Step-by-step explanation:
A percent is a ratio out of 100, as this answer is out of 100, the percent is just 9 2/3%.
Its 1400 divided by 224 so it will be 6.25 times