If π is rounded to a whole number, what is a reasonable estimate for the circumference of a circle with a diameter of 9 cm?

1 answer:

8 0

Pi rounded to a whole number would equal three. Circumference equals 2pi*r. The radius in this case is half of the diameter, so 4.5 cm. 2 times pi, or three equals 6 times 4.5 is 27

You might be interested in

The total distance in centimeters that a toy robot moves varies directly with the time in seconds the toy robot moves a total di

kobusy [5.1K]

Answer:

Hey there!

The robot moves 63 cm in 9 seconds. Then in 1 second, it moves 7 cm.

If it goes 49 cm, it will take 7 seconds.

Let me know if this helps :)

4 0

2 years ago

Ethan bought 4 packages of pencils. After he gave 8 pencils to his friends, he had 40 pencils left over. How many pencils were i

swat32

Answer:

12 pencils in each package.

Step-by-step explanation:

Given:

Ethan bought 4 packages of pencils.

No of Packages = 4

No of pencils given to friend = 8 pencils

No of pencils left over =40 pencils

∴Total Number of Pencils = No of pencils given to friend + No of pencils left over = $40+8 =48$

Total Number of pencils in each package = $\frac{\textrm{Total Number of Pencils}}{\textrm{No Of Packages}}= \frac{48}{4}= 12 \ pencils$

8 0

2 years ago

The general form of the equation of a circle is 7x2 + 7y2 − 28x + 42y − 35 = 0. The equation of this circle in standard form is

Ede4ka [16]

Answer:

The standard form of a circle is (x-h)^2 + (y-k)^2 = r^2 with (h,k) being the center of the circle and r being the radius. In this case the circle's equation in standard form is (x-2)^2 + (y+3)^2 = 18. Knowing this it's easy to see that the center of the circle (h,k) is (2,-3). Finally the radius is $\sqrt{18}$ or in simplified terms, 3 $\sqrt{2}$

Step-by-step explanation:

7 0

2 years ago

Read 2 more answers

Given: Circle X with a Radius r and circle Y with radius s Prove: Circle x is similar to circle y

lana [24]

Two figures are similar if one is the scaled version of the other.

This is always the case for circles, because their geometry is fixed, and you can't modify it in anyway, otherwise it wouldn't be a circle anymore.

To be more precise, you only need two steps to prove that every two circles are similar:

Translate one of the two circles so that they have the same center
Scale the inner circle (for example) unit it has the same radius of the outer one. You can obviously shrink the outer one as well

Now the two circles have the same center and the same radius, and thus they are the same. We just proved that any two circles can be reduced to be the same circle using only translations and scaling, which generate similar shapes.

Recapping, we have:

Start with circle X and radius r
Translate it so that it has the same center as circle Y. This new circle, say X', is similar to the first one, because you only translated it.
Scale the radius of circle X' until it becomes $s$ . This new circle, say X'', is similar to X' because you only scaled it