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3 years ago

The diameter of a circle is 4 in. Find its area in terms of π\pi π.

Mathematics

2 answers:

sergey [27]3 years ago

5 0

Answer:

If the diameter of the circle is 4 in. then the radius of the circle is 2

the formula for the circle area is

A = πr^2

r = radius

A = π * 2 * 2

A = 12.57 if solved

Step-by-step explanation:

Serggg [28]3 years ago

4 0

The formula for area of a circle is r² x π.

Since we know the diameter, we can firstly divide by 2 to find our radius.

4/2 = 2

Now that we know the radius, we can substitute it in and square the value.

(2)² x π

(4) x π

Since we're finding the area in terms of pi, we won't multiply by pi, giving us the answer of 4π.

Therefore, the area of the circle is equal to 4π.

Hope this helped! :)

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Math question I need help with

Greeley [361]

F(x) = (x - 4) (x^2 + 4) would be your answer.

4 0

3 years ago

(7i)(-4i) a. -28i b. 28 c. -28 d. -32i

levacccp [35]

Hey!

Explanation:

↓↓↓↓↓↓↓↓↓↓

First, remove parenthesis.

$7i4i$

Secondly, multiple by the numbers.

$7*4=28$

$-28ii$

Third, apply exponents rule.

$-28i^2$

$i^2=-1$

$-28(-1)$

Finally, refine.

$=28\\$

Answer⇒⇒⇒⇒28

Hope this helps!

Thank you for posting your question at here on Brainly.

Have a great day!

-Charlie

6 0

3 years ago

Three listening stations located at (3300, 0), (3300, 1100), and (-3300, 0) monitor an explosion. The last two stations detect t

erastovalidia [21]

Answer:

The coordinates of the explosion is (3300, -2750)

Step-by-step explanation:

I have plot the points and attached to thus answer for easy understanding.

Now, from the question, since station A is the first to hear the explosion, we'll make it the foci of the parabola in the graph I attached and it will be horizontal since the distance between station C and A is much more than that between station B and A. Thus, the reason why station C will have to be the other foci with the hyperbola centred at the origin.

Now, sound travels at a speed of 1100 ft/s and station B is located 1100 ft from station A. Thus, the explosion would likely have occurred at a point on the line x = 3300ft . Since station A is 3300ft from centre C = 3300,hence C² = 3300² = 10,890,000. Since it takes 4 seconds longer for the sound to reach station C than A, the sound has traveled 4(1100)= 4400 ft.

Thus, 4400 = d1 = d2 = 2a

So,2a = 4400 and so, a =2200

a² = 2200² = 4,840,000 where d1 is the distance from station C to the explosion and d2 is the distance from station A to the explosion. To find b², let's use the equation ;

c² = a² + b² and so; b² = c² - a² = 10,890,000 - 4,840,000 = 6,050,000

Equation of hyperbola is given as;

(x²/a²) - (y²/b²) = 1

Plugging in the values of a² and b², we obtain ;

(x²/4,840,000) - (y²/6,050,000) = 1

Since we have deduced that the explosion must occur on the line x= 3300, we'll put in 3300 for x to obtain ;

(3300²/4,840,000) - (y²/6,050,000) = 1

2.25 - 1 = (y²/6,050,000)

y² = (1.25 x 6,050,000)

y² = 7562500

y = √7562500

y = ± 2750

Due to the fact that the explosion will occur at a point further from station B than from station A, the explosion will take place in quadrant 4. Thus, we will take the negative value of y which is - 2750.

So explosion will occur at the coordinate (3300, -2750)