Points for points?

A rectangular box is 32 cm wide and 36 cm high. If the surface area of the box is 4344 square centimeters, find the length of t

AnnZ [28]

To find the surface area, multiply length x width x height.

let "length" = l

l x 32 x 36 = 4344

Simplify

l x (32 x 36) = 4344

l x 1152 = 4344

Isolate the length. Divide 1152 from both sides

(l x 1152)/1152 = (4344)/1152

l = 4344/1152

l = 3.77 (rounded)

3.77 cm is your length.

hope this helps

8 0

3 years ago

Annita, Gary, and Tara all run races. Annita has 7 less than 4 times the number of race medals as Tara. Gary has 13 more than 2

harkovskaia [24]

Answer:

4 t - 7 = 2 t+ 13 is the required equation.

The number of race medals Tara has is t = 20 medals.

Step-by-step explanation:

Let the number of medals Tara has = t medals

So, the number of medal Anita has = 4( Medals of Tara) - 7

= 4t - 7

And the number of medals Gary has = 2 times (Medals of Tara) + 13

= 2(t) + 13 = 2t + 13

Now, Annita and Gary has same number of medals.

⇒ 4t - 7 = 2t+ 13

or, 4t - 2t = 7 + 13

⇒ 2t = 20

⇒ t = 20/2 = 10

or t = 10

Hence, the number of race medals Tara has is t = 20 medals

6 0

3 years ago

In physics, we can find the amount of force needed to push or pull an object by multiplying the object’s mass by the object’s ac

Kisachek [45]

Answer:

1875

Step-by-step explanation:

750 x 2.5 = 1,875

6 0

2 years ago

Name/ Uid:1. In this problem, try to write the equations of the given surface in the specified coordinates.(a) Write an equation

Gemiola [76]

To find:

(a) Equation for the sphere of radius 5 centered at the origin in cylindrical coordinates

(b) Equation for a cylinder of radius 1 centered at the origin and running parallel to the z-axis in spherical coordinates

Solution:

(a) The equation of a sphere with center at (a, b, c) & having a radius 'p' is given in cartesian coordinates as:

$(x-a)^{2}+(y-b)^{2}+(z-c)^{2}=p^{2}$

Here, it is given that the center of the sphere is at origin, i.e., at (0,0,0) & radius of the sphere is 5. That is, here we have,

$a=b=c=0,p=5$

That is, the equation of the sphere in cartesian coordinates is,

$(x-0)^{2}+(y-0)^{2}+(z-0)^{2}=5^{2}$

$\Rightarrow x^{2}+y^{2}+z^{2}=25$

Now, the cylindrical coordinate system is represented by $(r, \theta,z)$

The relation between cartesian and cylindrical coordinates is given by,

$x=rcos\theta,y=rsin\theta,z=z$

$r^{2}=x^{2}+y^{2},tan\theta=\frac{y}{x},z=z$

Thus, the obtained equation of the sphere in cartesian coordinates can be rewritten in cylindrical coordinates as,

$r^{2}+z^{2}=25$

This is the required equation of the given sphere in cylindrical coordinates.

(b) A cylinder is defined by the circle that gives the top and bottom faces or alternatively, the cross section, & it's axis. A cylinder running parallel to the z-axis has an axis that is parallel to the z-axis. The equation of such a cylinder is given by the equation of the circle of cross-section with the assumption that a point in 3 dimension lying on the cylinder has 'x' & 'y' values satisfying the equation of the circle & that 'z' can be any value.

That is, in cartesian coordinates, the equation of a cylinder running parallel to the z-axis having radius 'p' with center at (a, b) is given by,

$(x-a)^{2}+(y-b)^{2}=p^{2}$

Here, it is given that the center is at origin & radius is 1. That is, here, we have, $a=b=0,p=1$ . Then the equation of the cylinder in cartesian coordinates is,

$x^{2}+y^{2}=1$

Now, the spherical coordinate system is represented by $(\rho,\theta,\phi)$

The relation between cartesian and spherical coordinates is given by,

$x=\rho sin\phi cos\theta,y=\rho sin\phi sin\theta, z= \rho cos\phi$

Thus, the equation of the cylinder can be rewritten in spherical coordinates as,

$(\rho sin\phi cos\theta)^{2}+(\rho sin\phi sin\theta)^{2}=1$

$\Rightarrow \rho^{2} sin^{2}\phi cos^{2}\theta+\rho^{2} sin^{2}\phi sin^{2}\theta=1$

$\Rightarrow \rho^{2} sin^{2}\phi (cos^{2}\theta+sin^{2}\theta)=1$

$\Rightarrow \rho^{2} sin^{2}\phi=1$ (As $sin^{2}\theta+cos^{2}\theta=1$ )

Note that $\rho$ represents the distance of a point from the origin, which is always positive. $\phi$ represents the angle made by the line segment joining the point with z-axis. The range of $\phi$ is given as $0\leq \phi\leq \pi$ . We know that in this range the sine function is positive. Thus, we can say that $sin\phi$ is always positive.

Thus, we can square root both sides and only consider the positive root as,

$\Rightarrow \rho sin\phi=1$

This is the required equation of the cylinder in spherical coordinates.

Final answer:

(a) The equation of the given sphere in cylindrical coordinates is $r^{2}+z^{2}=25$

(b) The equation of the given cylinder in spherical coordinates is $\rho sin\phi=1$

7 0

3 years ago

Use the marked parallel lines to find the value of y in the diagram below (1 point)

Inessa [10]

2x + 5 = 3x - 45 [alternate interior angles]
3x - 2x = 5 + 45
x = 50

4y - 1 + 2x + 5 = 180 [supplementaly angles]
4y + 2(50) + 4 = 180
4y + 100 = 176
4y = 76
y = 19

7 0

3 years ago