Really CONFUSING math??plz help?

Question

1) A circle has a circumference of 12cm. (what the h**l is circumference)

What is the raduis of the circle in cm? What is the area of the circle in cm^2? What is the area of this circle in mm^2?

2) If a circle has an area of 16cm^2: what is the raduis of the circle in cm? What is the circumference?

3) a rectangle is twice as long as it is wide. If the width of the rectangle is 3 inch, what is the rectangle's area, in square inches?

4) Given that D= R x T, find T when R = 55 mph and D = 385 miles. Be sure to include proper units.

5) solve for x: -(1 + 7x) -6(-7 - x) = 36....distribute the negative, combine like terms, this is where I'm stuck.

for the problems can you please explain how you get the numbers? Because I want to learn it for myself so I don't ever have to ask again.

Answer 1

wat the **** this isnt math yo

Answer 2

1.  Circumference is the distance around a circle.  You must not be listening or reading or own a dictionary.  The formula for circumference is circumference = d x pi  d is the diameter and pi is 3.14.  Therefore the diameter is 12 divided by pi and the radius is one half of that.  The area would then be pi times radius squared.

2.  Area = pi x radius squared.

     16  = pi x r squared

      16/pi = r squared

     find the square root of 16/3.14 and you have the answer

3.  If length = 2x width. the length is 2 x 3 or 6.  This makes the dimensions 3 x 6.  3 x 6 is 18, so the answer is 18 square inches.

4.  D=Rxt

     385miles = 55miles/hour  x T

     385 miles/55miles/hour = T

     Therefore, T= 7 hours

5.  -(1+7x) -6(-7-x) = 36

    go ahead and do the multiplication first in order to keep your positive and negatives correct

    -1-7x+42+6x = 36  (remember a minus times a positive is a negative and a minus times a minus is a positive)

    Combine the like terms (x's with x's and numbers with numbers)

    -1+42-7x+6x = 36

    41 - x = 36

subtract 41 from both sides of the equation

    0 -x = 36-41

    -x = -5divide both side of the equation by -1

    x = 5

Algebra is not that difficult, but it appears you need to learn some definitions of terms:  circumference, radius, diameter, pi, are.

Answer 3

Question 1

Circumference is distance around circle.

Points on the circumference are equidistant from centre of circle.

C = 2 π r

12 = 2 π r

6 = π r

r = 6 / π

r = 1.91 cm

A = π (1.91)² cm²

A = 11.5 cm²

A = 1150 mm²

Question 2

r² = A / π

r² = 16 / π

r = √ (16 / π)

r = 2.26 cm

Question 3

W = 3 ins

L = 6 ins

A = 18 in²

Question 4

T = D / R

T = 385 / 55 h

T = 7 h

Question 5

- 1 - 7x + 42 + 6x = 36

41 - x = 36

x = 5

Answer 4

Dera, Marine

1. C = 2*pi*r

   12 = 2*3.14*r

   r = 6/3.14

   r = 1.91 cm

   A = pi * r^2

      = 3.14 * (1.91)^2

      = 11.46 cm^2 = 11.46 * 100 = 1146 mm^2

2.  You may use the same formula as number 1. Pi = 3.14 or 22/7.

3. A = length * width

   length = 2xwidth

   A = 2 * 3 * 3 = 18 square inches

4. D = R x T

   T = D / R

   T = 385 MILES / 55 MPH

   T = 7 HOURS

5. -(1 + 7x) -6(-7 - x) = 36

    -1 - 7x + 42 + 6x = 36

    -x + 41 = 36

    -x = -5

     x = 5

I hope those may help you. Welcome to tell me if there's something confusing on the formulas above.

I'm happy to help you.

Thank you.

Answer 5

1) circumference is the distance around a circle (like perimeter for a rectangle or square). the formula for circumference is "2*pi*radius". so make an equation setting the circumference of the circle equal to the equation: "12=2*pi*radius" and solve for radius. to find area plug the answer you got for the radius into the equation for area: pi*radius^2. to find the area in mm, just convert the answer from cm to mm.

2) A=pi*radius^2. so plug 16 into that equation. 16=pi*radius^2. plug the answer you get from that into the circumference equation: C=2*pi*radius

3) first find the length of the rectangle, which is two times the width. 3*2=6. therefore the demensions of the rectangle are 6 and 3. to find the area you multiply the length times the width: 6 * 3 = __

4) again, all you have to do is plug the numbers you were given into the equation. 385=55*T. then switch it around so you can solve for T, the unknown. T = 385 / 55

5) first you have to distribute whatever's outside the parentheses. so destribute the negative and you'll get "-1 - 7x" then do the same with the -6, multiplying it by everything inside the parentheses and you get "42 + 6x". then you add the two equations: "-1 - 7x + 42 + 6x"

i hope that helped!!!

Answer 6

1) circumference is distance around the circle.

to find it, do 2pir, when pi is a constant about 3.14, so to do this, just plug in what you have and solve for what you dont.

12=2pir

r=12/(2pi) cm

area is pi(r)^2

pi(12/(2pi))^2

144/(4pi)

36/pi cm^2

for mm^2, just multiply r by 1000

pi(12000/(2pi))^2

6000^2/pi mm^2

2) pir^2=A

16=pir^2

16/pi=r^2

r=sqrt(16/pi) cm

C=2pir

2pi(sqrt(16/pi)) cm

3) 3(6)=18 in^2

4) 385=55T

T=385/55

T=7 hours

5) -(1 + 7x) -6(-7 - x) = 36

-1-7x+42+x=36

-6x+41=36

-6x=-5

x=5/6

make it a good day