9.75 divided by 5 equals

Which statements about finding the area of the equilateral triangle are true? Check all that apply.

lara31 [8.8K]

Answer:

The correct options are 1, 2 and 4.

Step-by-step explanation:

The given triangle is an equilateral triangle. All the sides of an equilateral triangle are same. All interior angles are equal with measure 60 degree.

The distance from the center of an equilateral triangle to the midpoint of a side is known as apothem. In the given figure letter a represents the apothem.

Point D is the midpoint of BC,

$b=\frac{BC}{2}=\frac{8.7}{2}=4.35$

Use Pythagorean theorem in triangle COD. So, option 1 is correct.

$OC^2=OD^2+DC^2$

$5^2=a^2+(4.35)^2$

$25=a^2+18.9225$

$a=\pm 2.46526$

$a\approx\pm 2.5$

The distance can not be negative, so the length of the apothem is approximately 2.5 cm. Option 4 is correct.

The line OC bisects the angle C.

$tan(30^{\circ})=\frac{a}{b}$

$\frac{1}{\sqrt{3}=\frac{a}{4.35}$

$a\approx\pm 2.5$

Therefore option 2 is correct.

The perimeter of an equality triangle is

$P=3a=3(8.7)=26.1$

Option 3 is incorrect.

$A=\frac{\sqrt{3}}{4}a^2=\frac{\sqrt{3}}{4}(8.7)^2=32.77$

Option 5 is incorrect.

Therefore options 1, 2 and 4 are correct.

3 0

3 years ago

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Greatest common factor of 66 and 32

scoundrel [369]

Hey there,

The Greatest Common Factor or the GCF of 66 and 32 would be 2.

Both of the numbers go into 2 and that is the highest common factor the two share.

Hope I helped,

Amna

8 0

3 years ago

today only, a sofa is being sold at a 36% discount. The sale price is $560. what was the price yesterday?

pashok25 [27]

Answer:

Step-by-step explanation:

Let yesterday's price be x

Discount percentage = 36%

Sale price = $ 560

(100-36)% of x = 560

64 % *x = 560

$\frac{64}{100}*x=560\\\\x=560*\frac{100}{64}\\\\x=875$

Yesterday's price = $ 875

8 0

3 years ago

Researchers are studying the distribution of subscribers to a certain streaming service in different populations. From a random

Katen [24]

Answer:

$CI = (0.17 - 0.27)\± 1.65\sqrt{\frac{(0.17)*(0.83) + (0.27)*(0.73)}{200}}$

Step-by-step explanation:

Given

$n = 200$

$x_1 = 34$ -- City C

$x_2 = 54$ --- City K

Required

Determine the 90% confidence interval

This is calculated using:

$CI = \bar x \± z\frac{\sigma}{\sqrt n}$

Calculating $\bar x$

$\bar x = \bar x_1 - \bar x_2$

$\bar x = \frac{x_1}{n} - \frac{x_2}{n}$

$\bar x = \frac{34}{200} - \frac{54}{200}$

$\bar x = 0.17 - 0.27$

For a 90% confidence level, the z-score is 1.65. So:

$z = 1.65$

Calculating the standard deviation $\sigma$

$\sigma = \sqrt{(\bar x_1)*(1 - \bar x_1) + (\bar x_2)*(1 - \bar x_2) }$

So:

$\sigma = \sqrt{(0.17)*(1 - 0.17) + (0.27)*(1 - 0.27) }$

$\sigma = \sqrt{(0.17)*(0.83) + (0.27)*(0.73)}$

So:

$CI = (0.17 - 0.27)\± 1.65\frac{\sqrt{(0.17)*(0.83) + (0.27)*(0.73)}}{\sqrt {200}}$

$CI = (0.17 - 0.27)\± 1.65\sqrt{\frac{(0.17)*(0.83) + (0.27)*(0.73)}{200}}$

7 0

2 years ago

Kevin can travel 22 1/2 miles in 1/3 hour. what is his average speed in miles per hour

klemol [59]

We know that speed * time = distance

Before we start we need to make sure the units for all three numbers are right

The time is 1/3 of a hour, 1/3*60 = 20 minutes

x * 20 = 22.5

x *2 * 10 = 22.5

2x = 2.25

x = 1.125

4 0

3 years ago

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