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3 years ago

What is the radius of the circle given by the equation x^2+y^2=49?

Mathematics

2 answers:

viktelen [127]3 years ago

8 0

The answer is "C. 7."

The equation of a circle is (x-h)²+(y-k)²=r². r² represents the radius squared, or multiplied by itself. 7 multiplied by 7 is equal to 49, so the radius of the circle would be 7.

Marta_Voda [28]3 years ago

7 0

Formula of the circle

(x-a)² +(y-b)² = r²,

where r is a radius, (a,b) - coordinates of the center.

So,

x² + y² = 49

(x-0)² + (y-0)² = 49.

Center of this circle has coordinates (0,0).

x² + y² = 7²

r = 7

Answer is C.7.

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Data given and notation

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$p_v$ represent the p value for the test (variable of interest)

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We need to conduct a hypothesis in order to determine if the mean is higher than 3.3, the system of hypothesis would be:

Null hypothesis: $\mu \leq 3.3$

Alternative hypothesis: $\mu > 3.3$

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z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

We can replace in formula (1) the info given like this:

$z=\frac{3.4-3.3}{\frac{0.4}{\sqrt{50}}}=1.768$

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Since is a one right tailed test the p value would be:

$p_v =P(z>1.768)=0.039$

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