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3 years ago

Each interior angle of a regular polygon measures 140 degrees how many sides does the polygon have

Mathematics

2 answers:

Semenov [28]3 years ago

7 0

The polygon has 9 sides.

$\frac{360}{n}$ = 40

360 = 40n

n = 9

180 - 140 = 40°

Therefore, the polygon has 9 sides.

anygoal [31]3 years ago

6 0

The sum of the measures of the interior angles of a polygon of n sides is
180(n - 2)

If the polygon is regular, all angles are congruent, and each angle measures
[180(n - 2)]/n

Set the measure of one angle equal to 140, and solve for n, the number of sides.

[180(n - 2)]/n = 140

180(n - 2) = 140n

180n - 360 = 140n

40n = 360

n = 9

The number of sides is 9.

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A necklace regularly sells for $18.00. the store advertises a 15% discount. what is the sale price of the necklace in dollars

SSSSS [86.1K]

I can solve with 2 methods:

I. Because the discount is 15 % of 18 $ , the price will be (100-15=85) 85 % of 18 $
18*85/100= 15,3 $ ( the sale price)

II. The discount is 15 % of 18$
15*18/100= 2,7$ ( the discount)
then I decrease it from the regularly price
18$-2,7$=15,3 $ (the sale price)

Personally I believe the first is an easier method.
I hope you understand and you can apply this in every similary problem.

6 0

3 years ago

Only need help with #'s 10, 12, 14, 16

gregori [183]

Im just about to work one out for you and you just do the same on the rest

7 0

3 years ago

I need to use the Pythagorean Theorem to find X. I don’t know how to do that!!

frutty [35]

Answer:

17) x=8

18) $x=\sqrt{189}$ or $x= 3\sqrt{21}$

Step-by-step explanation:

So the rule is $a^{2} +b^{2} =c^{2}$ , "c" being the hypothenuse, or the long line that is opposite to the right angle.

17) We know that both values of x are equal to each other, which makes everything 10x easier!

$x^{2} +x^{2} =(8\sqrt{2}) ^{2}$

(by the way we know the x values are our a and b values because they are legs! the way I like to remember the legs is that they are connected to the right angle box, and therefore support the hypothenuse)

<em>simplify</em> (╥︣﹏╥)

$2x^2=8^2(\sqrt{2} )^{2}$

$2x^2=64(2)$

$2x^2=128$

$x^{2}= 128/2$

$x^{2} =64$

x=8

18) Just pretend that the flipped triangle doesn't exist. It's parallel to the other triangle with values on it, and basically servers no purpose other than being parallel to the sister triangle :)

Anyways, since we know the hypothenuse (15) but we don't know one of our leg values (x), we're going to change our equation a bit!

$c^{2} - b^{2} = a^{2}$