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nalin [4]
3 years ago
13

Find the area of the following circles. a. A circle with a 8-inch radius b. A circle with a 10-kilometer radius c. A circle with

a 14-yard diameter d. A circle with a 22-centimeter diameter
Mathematics
2 answers:
natima [27]3 years ago
8 0

Answer: A. 201.14inches²

B. 314.28km²

C. 154yds²

D. 380cm²

Step-by-step explanation: the area of a circle is given by [pie] (22/7) multiplied by the square of the radius

Radius is half the diameter of the circle

Applying the formula 22/7 x r²:

A. 22/7 x 8² = 201.4inch²

B. 22/7 x 10² = 314.28km²

C. 22/7 x (14/2)² = 154yd²

D. 22/7 x (22/2)² = 380cm²

Kudos!

Thepotemich [5.8K]3 years ago
5 0
Area of a circle is A= \pi r^2.  The first one, a, the radius squared is 8*8=64.  So A=64 \pi.  If you multiply in pi as 3.14, you'll have 200.96 square inches.  The second one, b, the radius squared is 10*10=100.  So A=100 \pi square kilometers.  If you multiply in pi as 3.14 you'll have 314 square kilometers.  The third one, c, the radius squared is 14*14=196.  So A=196 \pi yd^2.  Or you could multiply in pi as 3.14 to get 615.44 yd squared.  For the last one, d, the radius squared is 22*22=484 cm.  Therefore, A=484 \pi cm^2, or multiply in 3.14 for pi to get 1519.76 cm squared.  There you go!
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Find two consecutive even integers such that the sum of the larger and twice the smaller is 62
bixtya [17]
2x and (2x +2)
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x = 10
So 2x = 20 (one of the integers) and 22 is the other


6 0
3 years ago
The floor of a new planetarium is a circle with a 13-yard diameter.A stage will occupy a quarter circle section of the floor.The
Naddik [55]

Answer:

<h3>$1,043.74</h3>

Step-by-step explanation:

Area of the circular floor = πr²

Since the stage only occupies a quarter circle section of the floor, then;

Area of the stage = πr²/4

Given

diameter of the floor = 13yd

radius = 13/2 = 6.5yd

Find the area of the stage;

Area of the stage = π(6.5)²/4

Area of the stage = 3.14(42.25)/4

Area of the stage = 33.16625yd²

If the material for the stage will cost $31.47 per square yard, this means;

1yd² = $31.47

33.16625yd² = x

Cross multiply

x = 33.16625*31.47

x = 1,043.74

Hence the stage will cost $1,043.74

5 0
3 years ago
Evaluate the algebraic expression h + h when b = 3, d = 12, h = 2 and r = 7.
zubka84 [21]
Given that h = 2,

h + h = 2 + 2
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4 0
3 years ago
Read 2 more answers
Use slope-intercept form to write the equation of a line
Korvikt [17]

Answer:

y=-3x-2

Step-by-step explanation:

There is enough information to make a point-slope form equation that which we can convert into slope-intercept form.

Point-slope form is: y-y_1=m(x-x_1)

We are given the slope of -3 and the point of (1,-5).

y-y_1=m(x-x_1)\rightarrow y+5=-3(x-1)

Convert into Slope-Intercept Form:

y+5=-3(x-1)\\y+5-5=-3(x-1)-5\\\boxed{y=-3x-2}

8 0
3 years ago
Calcium is essential to tree growth because it promotes the formation of wood and maintains cell walls. In 2010, the concentrati
sergij07 [2.7K]

Answer:

The p-value obtained from the hypothesis test is greater than the significance level at which the test was performed, hence, we fail to reject the null hypothesis & say that there isn't enough evidence from the sample to conclude that the the calcium concentrations have changed since 2010.

Step-by-step explanation:

To perform this test, we need to first obtain the sample mean and sample standard deviation.

The data is 0.065 0.087 0.070 0.262 0.126 0.183 0.120 0.234 0.313 0.108

Mean = (sum of variables)/(sample size)

= (0.065+0.087+0.070+0.262+0.126+0.183+0.120+0.234+0.313+0.108)/10

= 0.1568 milligram per liter

Standard deviation = σ = √[Σ(x - xbar)²/N]

Σ(x - xbar)² = 0.00842724+0.00487204+0.00753424+0.01106704+0.00094864+0.00068644+0.00135424+0.00595984+0.02439844+0.00238144

= 0.0676296

σ = √[Σ(x - xbar)²/N] = √(0.0676296/10) = 0.08224 milligrams per liter

To do an hypothesis test, we need to first define the null and alternative hypothesis

The null hypothesis plays the devil's advocate and usually takes the form of the opposite of the theory to be tested. It usually contains the signs =, ≤ and ≥ depending on the directions of the test.

While, the alternative hypothesis usually confirms the the theory being tested by the experimental setup. It usually contains the signs ≠, < and > depending on the directions of the test.

For this question, the null hypothesis would be that there is no significant evidence to suggest that the the calcium concentrations have changed since 2010. That is, the calcium concentrations haven't changed since 2010.

The alternative hypothesis is that there is significant evidence to suggest that the the calcium concentrations have changed since 2010. That is, the calcium concentrations haven't changed since 2010.

Mathematically,

The null hypothesis is represented as

H₀: μ = 0.11 milligrams per liter

The alternative hypothesis is given as

Hₐ: μ ≠ 0.11 milligrams per liter

To do this test, we will use the t-distribution because no information on the population standard deviation is known

So, we compute the t-test statistic

t = (x - μ₀)/σₓ

x = sample mean = 0.1568 milligram per liter

μ₀ = the mean calcium concentrations from 2010 = 0.11 milligrams per liter

σₓ = standard error = (σ/√n)

where n = Sample size = 10

σ = Sample standard deviation = 0.08224 milligrams per liter

σₓ = (σ/√n) = (0.08224/√10) = 0.026

t = (0.1568 - 0.11) ÷ 0.026

t = 1.80

checking the tables for the p-value of this t-statistic

Degree of freedom = df = 10 - 1 = 10 - 1 = 9

Significance level = 0.05

The hypothesis test uses a two-tailed condition because we're testing in two directions. (Greater than and less than)

p-value (for t = 1.80, at 0.05 significance level, df = 9, with a two tailed condition) = 0.105391

The interpretation of p-values is that

When the (p-value > significance level), we fail to reject the null hypothesis and when the (p-value < significance level), we reject the null hypothesis and accept the alternative hypothesis.

So, for this question, significance level = 0.05

p-value = 0.105391

0.105391 > 0.05

Hence,

p-value > significance level

This means that we fail to reject the null hypothesis & say that there isn't enough evidence to conclude that the the calcium concentrations have changed since 2010.

Hope this Helps!!!

8 0
3 years ago
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