All categories

2 years ago

An FM radio station signal travels in a 40-mile radius. An AM radio station

Mathematics

1 answer:

MrMuchimi2 years ago

3 0

Answer:

4976.28 square miles (nearest hundredth)

Step-by-step explanation:

$\textsf{Area of a circle}=\pi r^2 \quad \textsf{(where r is the radius)}$

FM radio station

Given:

r = 40 miles

$\implies \textsf{Area}=\pi (40)^2=1600 \pi \: \sf miles^2$

AM radio station

Given:

r = 4 miles

$\implies \textsf{Area}=\pi (4)^2=16 \pi \: \sf miles^2$

Difference:

$\begin{aligned}\implies \textsf{FM area - AM area} & =1600 \pi - 16 \pi\\ &= 1584 \pi\\ & =4976.23\:\textsf{square miles (nearest hundredth)}\end{aligned}$

You might be interested in

CAN SOMEONE PLEASE HELP!!!

Andreas93 [3]

Step-by-step explanation:

AC=AB+BC-cos. AC=100+66-cos. AC=166-0.906. AC=√165.094. AC=12.8

4 0

2 years ago

A red car is driving along the road in the direction of the police car and is 130 feet up the road from the location of the poli

pishuonlain [190]

Complete question:

A police car is located 50 feet to the side of a straight road. A red car is driving along the road in the direction of the police car and is 130 feet up the road from the location of the police car. The police radar reads that the distance between the police car and the red car is decreasing at a rate of 75 feet per second. How fast is the red car actually traveling along the road.

Answer:

The red car is traveling along the road at 80.356 ft/s

Step-by-step explanation:

Given

Police car is 50 feet side off the road

Red car is 130 feet up the road

Distance between them is decreasing at the rate of 75 feet per sec

Let x be how far the police is off the road.

Let y be how far the red car is up the road.

Let h be the distance between the police and the red car.

This forms a right triangle so we can use the Pythagorean theorem, to solve for h

h² = x² + y²

h² = 50² + 130²

h² = 19400

h = √19400

h = 139.284 ft

Again;

Let dx/dt be how fast the police is traveling toward the road.

Let dy/dt be how fast the red car is traveling along the road.

Let dh/dt be how fast the distance between the police and the car is decreasing.

Recall that, h² = x² + y² (now differentiate with respect to time, t)

2h(dh/dt) = 2x(dx/dt) + 2y(dy/dt)

divide through by 2

h(dh/dt) = x(dx/dt) + y(dy/dt)

since the police car is not, dx/dt = 0

and dy/dt is the how fast is the red car actually traveling along the road

139.284(75) = 50(0) + 130(dy/dt)

10446.3 = 0 + 130(dy/dt)

dy/dt = 10446.3 / 130

dy/dt = 80.356 ft/s

Therefore, the red car is traveling along the road at 80.356 ft/s

6 0

3 years ago

A horse ate 1.8 pounds of grass in 4 days how many grass can the horse eat for 7 days

jolli1 [7]

i think the answer to this is 3.15

4 0

3 years ago

Read 2 more answers

The system of equations y = - 2x + 3 and y = xis graphed. What is the solution to the system of equations ?

nata0808 [166]

Answer:

(1,1)

Step-by-step explanation:

we have

$y=-2x+3$ ----> equation A

$y=x$ ----> equation B

we know that

The solution of the system of equations is the intersection point both graphs

The intersection point both graphs is the point (1,1)

see the given graph

therefore

The solution is the point (1,1)

Remember that

if a ordered pair is a solution of a system of equations then the ordered pair must satisfy both equations of the system

Verify

Substitute the value of x=1 and y=1 in each equation and analyze the result

Equation A

$1=-2(1)+3$

$1=1$ ---> is true

The ordered pair satisfy the equation A

Equation B

$1=1$ ---> is true

The ordered pair satisfy the equation B

therefore

The ordered pair (1,1) is a solution of the system because satisfy both equations

5 0

3 years ago

Read 2 more answers

Write and equation of the translated or rotated graph in general form (picture below)

WINSTONCH [101]

Answer:

The answer is hyperbola; (x')² - (y')² - 16 = 0 ⇒ answer (a)

Step-by-step explanation:

* At first lets talk about the general form of the conic equation

- Ax² + Bxy + Cy² + Dx + Ey + F = 0

∵ B² - 4AC < 0 , if a conic exists, it will be either a circle or an ellipse.

∵ B² - 4AC = 0 , if a conic exists, it will be a parabola.

∵ B² - 4AC > 0 , if a conic exists, it will be a hyperbola.

* Now we will study our equation:

xy = -8

∵ A = 0 , B = 1 , C = 0

∴ B² - 4 AC = (1)² - 4(0)(0) = 1 > 0

∴ B² - 4AC > 0

∴ The graph is hyperbola

* The equation xy = -8

∵ We have term xy that means we rotated the graph about

the origin by angle Ф

∵ Ф = π/4

∴ We rotated the x-axis and the y-axis by angle π/4

* That means the point (x' , y') it was point (x , y)

- Where x' = xcosФ - ysinФ and y' = xsinФ + ycosФ

∴ x' = xcos(π/4) - ysin(π/4) , y' = xsin(π/4) + ycos(π/4)

∴ x' = x/√2 - y/√2 = (x - y)/√2

∴ y' = x/√2 + y/√2 = (x + y)/√2

* Lets substitute x' and y' in the 1st answer

∵ (x')² - (y')² - 16 = 0

∴ $(\frac{x-y}{\sqrt{2}})^{2}-(\frac{x+y}{\sqrt{2}})^{2}=$

( $\frac{x^{2}-2xy+y^{2}}{2})-(\frac{x^{2}+2xy+y^{2}}{2})-16=0$

* Lets open the bracket

∴ $\frac{x^{2}-2xy+y^{2}-x^{2}-2xy-y^{2}}{2}-16=0$

* Lets add the like terms

∴ $\frac{-4xy}{2}-16=0$

* Simplify the fraction

∴ -2xy - 16 = 0

* Divide the equation by -2

∴ xy + 8 = 0

∴ xy = -8 ⇒ our equation

∴ Answer (a) is our answer

∴ The answer is hyperbola; (x')² - (y')² - 16 = 0

* Look at the graph:

- The black is the equation (x')² - (y')² - 16 = 0

- The purple is the equation xy = -8

- The red line is x'

- The blue line is y'

6 0

3 years ago

Read 2 more answers