Find the length of the radius. Assume that lines which appear to be tangent are tangent.

Mathematics

1 answer:

aleksley [76]3 years ago

3 0

The Answer Is 7.5

Tangent and 8 makes a right triangle, which is great because you could find the diameter and divide it by 2 to find the radius.

64+d^2=289

d^2=225

d=15

15/2=7.5

You might be interested in

What is 140 1/8 in radical form?

posledela

140 1/8 can not be expressed in radical form because it neither has an exponent or a square root. Unless if 140 is raised to the power of 1/8, then that can be.

8 0

3 years ago

The parabola below is a graph of the equation, . -y^2+x=-4

serious [3.7K]

The parabola divises the plan into 2 parts. Part 1 composes the point A, part 2 composes the points C, D, F.
+ All the points (x;y) satisfies: -y^2+x=-4 is on the parabola.
+ All the points (x;y) satisfies: -y^2+x< -4 is in part 1.
+ All the points (x;y) satisfies: -y^2+x> -4 is in part 2.

And for the question: "Which of the points satisfy the inequality, -y^2+x<-4"
we have the answer: A and E

4 0

3 years ago

A doctor wants to estimate the mean HDL cholesterol of all 20- to 29-year-old females. The number of subjects needed to estima

Ludmilka [50]

Answer:

$n=(\frac{1.64(14.7)}{3})^2 =64.57 \approx 65$

So the answer for this case would be n=65 rounded up to the nearest integer

And the sample size would decrease by 160-65=95 subjects

Step-by-step explanation:

1) Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s represent the sample standard deviation

n represent the sample size

ME represent the margin of error

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

2) Solution to the problem

Since the new Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.05,0,1)".And we see that $z_{\alpha/2}=1.64$