Identify the solution and graph of the given inequality.<br> p 5/14<br> p

Find the area of an octagon whose perimeter is 120 cm.

stira [4]

Answer:

The area of an octagon whose perimeter is 120 cm is 1086.4 $cm^{2}$

Step-by-step explanation:

An octagon is a polygon with eight sides. If the lengths of all the sides and the measurement of all the angles are equal, the octagon is called a regular octagon.

There is a predefined set of formulas for the calculation of perimeter, and area of a regular octagon.

The perimeter of an Octagon is given by

$P=8a$

and the area of an Octagon is given by

$A=2a^{2}(1+\sqrt{2})$

We know that the perimeter is 120 cm, solving for side length (a) in the perimeter formula we get

$120=8a\\\frac{8a}{8}=\frac{120}{8}\\a=15$

Now, we calculate the area

$A=2a^{2}(1+\sqrt{2})\\A=2(15)^{2}(1+\sqrt{2})\\A=450\left(1+\sqrt{2}\right)\\A\approx 1086.4 \:cm^{2}$

5 0

3 years ago

Find the equation of the line that passes through the points (-5,7) and (2,3)

Olegator [25]

Answer:

$y=-\frac{4}{7}x+4\frac{1}{7}$

Step-by-step explanation:

So, in order to solve this problem, I started off by drawing it out. On my graph that I have attached below, I first started out by locating the points (-5,7) and (2,3). Now, this is an optional step, but I highly encourage practicing your graphing skills by solving this problem on graph paper as well. Next, I connected the two points that I just graphed. This is the line that passes through (-5,7) and (2,3).

Now, here is where the actual solving starts. If you haven't already been taught this yet, I will introduce it to you now. I am going to find the equation of this line by filling in what I know in the equation y=mx+b, where m= the slope of the line, and b= y intercept.

Slope of the line: m= $\frac{y_{1} - y_{2} }{x_{1} - x_{2} } = \frac{7-3}{-5-2} = \frac{4}{-7}= -\frac{4}{7}$

If you haven't been taught how to find the slope of a line I recommend you find out.

Substitute the slope into the equation.

$y=-\frac{4}{7} x+b\\$

Now, we will solve for the 'b,' or y intercept.

We already have x and y values to use: (-5,7) or (2,3). I'll use x=2 and y=3 to solve for the y intercept.

$y=-\frac{4}{7} x+b\\\\3=-\frac{4}{7} *2+b\\\\3=-\frac{8}{7} +b\\b=3+\frac{8}{7} \\b=\frac{21}{7}+\frac{8}{7}=\frac{29}{7} =4\frac{1}{7} \\b=4\frac{1}{7}$