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2 years ago

Find the area of the regular octagon.

Mathematics

1 answer:

user100 [1]2 years ago

4 0

Answer:

236.59mm²

Step-by-step explanation:

The formula for the area of a regular polygon is 1/2ap, with a being the apothem and p being the perimeter.

To start, get the perimeter by multiplying 7 (one side of the polygon) by 8 to get 56.

Next, we have to find the apothem (the perpendicular segment from the center of the polygon to one of the sides).

First, create a right triangle on an of the polygon's sides, where the hypotenuse is equal to the radius of the polygon, one of the legs is the apothem, and the other leg is equivalent to half of the side.

Next, using the polygon angle formula (n-2(360)/n), we can get the base angle of the triangle, 1/2(135), or 67.5.

We can use this angle and some trigonometry to find the the apothem.

First, use SOHCAHTOA to figure out if you will use sine, cosine, or tangent (in this case, tangent).

Next, set up an equation using the tangent of 67.5 to find the apothem - tan67.5 = a/3.

And set the equation equal to a (a = 3.5tan67.5).

Now that you have the apothem, plug it into the area formula to get A = 1/2(56)(3.5tan67.5) and solve!

(28)(3.5tan67.5)

(28)(8.4497)

236.59mm²

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Given that R = 8 x + 4 y Find y when x = 8 and R = 30 Give your answer as an improper fraction in its simplest form.

QveST [7]

Answer:

25/8

Step-by-step explanation:

Given That:

R = 8x+4y

X= 8

R = 30.

So, 8 x 8 +4y = 30

Simplify, Rearrange and solve.

64 + 4y = 30

4y = 30/64 = 15/32

y = 15/32 divided by 4

y = 15 / 32 x 1/4

y = 15/(32 x 4) = 15/128

hope this helps

4 0

3 years ago

Complete the identity. 1) sec^4 x + sec^2 x tan^2 x - 2 tan^4 x = ?

Alecsey [184]

Answer:

See Explanation

Step-by-step explanation:

Question like this are better answered if there are list of options; However, I'll simplify as far as the expression can be simplified

Given

$sec^4 x + sec^2 x tan^2 x - 2 tan^4 x$

Required

Simplify

$(sec^2 x)^2 + sec^2 x tan^2 x - 2 (tan^2 x)^2$

Represent $sec^2x$ with a

Represent $tan^2x$ with b

The expression becomes

$a^2 + ab- 2 b^2$

Factorize

$a^2 + 2ab -ab- 2 b^2$

$a(a + 2b) -b(a+ 2 b)$

$(a -b) (a+ 2 b)$

Recall that

$a = sec^2x$

$b = tan^2x$

The expression $(a -b) (a+ 2 b)$ becomes

$(sec^2x -tan^2x) (sec^2x+ 2 tan^2x)$

..............................................................................................................................

In trigonometry

$sec^2x =1 +tan^2x$

Subtract $tan^2x$ from both sides

$sec^2x - tan^2x =1 +tan^2x - tan^2x$

$sec^2x - tan^2x =1$

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Substitute 1 for $sec^2x - tan^2x$ in $(sec^2x -tan^2x) (sec^2x+ 2 tan^2x)$

$(1) (sec^2x+ 2 tan^2x)$

Open Bracket

$sec^2x+ 2 tan^2x$ ------------------This is an equivalence

$(secx)^2+ 2 (tanx)^2$

Solving further;

................................................................................................................................

In trigonometry

$secx = \frac{1}{cosx}$

$tanx = \frac{sinx}{cosx}$

Substitute the expressions for secx and tanx

................................................................................................................................

$(secx)^2+ 2 (tanx)^2$ becomes

$(\frac{1}{cosx})^2+ 2 (\frac{sinx}{cosx})^2$

Open bracket

$\frac{1}{cos^2x}+ 2 (\frac{sin^2x}{cos^2x})$

$\frac{1}{cos^2x}+ \frac{2sin^2x}{cos^2x}$

Add Fraction

$\frac{1 + 2sin^2x}{cos^2x}$ ------------------------ This is another equivalence

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In trigonometry

$sin^2x + cos^2x= 1$

Make $sin^2x$ the subject of formula

$sin^2x= 1 - cos^2x$

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Substitute the expressions for $1 - cos^2x$ for $sin^2x$

$\frac{1 + 2(1 - cos^2x)}{cos^2x}$

Open bracket

$\frac{1 + 2 - 2cos^2x}{cos^2x}$

$\frac{3 - 2cos^2x}{cos^2x}$ ---------------------- This is another equivalence

8 0

3 years ago

Frankie the frog stands at the number 0 on a number line and wants to hop to the number 8. he can hop 1, 2, 3 units forward in a

ycow [4]

In order to hop 8 units, you can do:

1 two-units hops, 2 three-units hops

4 two-units hops

1 one-unit hops, 2 two-units hops, 1 three-units hops

2 one-unit hops, 2 three-units hops

2 one-unit hops, 3 two-units hops

3 one-unit hops, 1 two-units hops, 1 three-units hops

4 one-unit hops, 2 two-units hops

5 one-unit hops, 1 three-units hops

6 one-unit hops, 1 two-units hops

8 one-unit hops

7 0

3 years ago

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Zarrin [17]

Answer:

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15,055 words.

Step-by-step explanation:

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3 years ago

One afternoon, 27 people withdraw $100 from an ATM. What was the overall change in the amount of money in the machine?

Usimov [2.4K]

Answer:

The change is a decrease of $2700.

Step-by-step explanation:

Given

Total Number of people = 27

Amount each person withdrew = $100

The total withdrawn amount by 27 people = 100 × 27

= $2700

Let M be the amount of money in the ATM at the beginning.

As $2700 was drawn from the ATM, therefore, the change the amount of money in the machine will be:

M - 2700

It means the change is a decrease of $2700.

3 0

3 years ago