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3 years ago

28 4/7 simplify chang percent to a fractiom

Mathematics

2 answers:

Tresset [83]3 years ago

6 0

4/7 to a percent is about 57 percent.

alukav5142 [94]3 years ago

4 0

The answer would be 28.5%.
28 4/7= 200/7
200/7= 28.5%

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WILL GIVE BRAINLIEST

galina1969 [7]

I used substitution
The answer is a

3 0

3 years ago

Change each of the following points from rectangular coordinates to spherical coordinates and to cylindrical coordinates.

FromTheMoon [43]

Answer and Step-by-step explanation: Spherical coordinate describes a location of a point in space: one distance (ρ) and two angles (Ф,θ).To transform cartesian coordinates into spherical coordinates:

$\rho = \sqrt{x^{2}+y^{2}+z^{2}}$

$\phi = cos^{-1}\frac{z}{\rho}$

For angle θ:

If x > 0 and y > 0: $\theta = tan^{-1}\frac{y}{x}$ ;

If x < 0: $\theta = \pi + tan^{-1}\frac{y}{x}$ ;
If x > 0 and y < 0: $\theta = 2\pi + tan^{-1}\frac{y}{x}$ ;

Calculating:

a) (4,2,-4)

$\rho = \sqrt{4^{2}+2^{2}+(-4)^{2}}$ = 6

$\phi = cos^{-1}(\frac{-4}{6})$

$\phi = cos^{-1}(\frac{-2}{3})$

For θ, choose 1st option:

$\theta = tan^{-1}(\frac{2}{4})$

$\theta = tan^{-1}(\frac{1}{2})$

b) (0,8,15)

$\rho = \sqrt{0^{2}+8^{2}+(15)^{2}}$ = 17

$\phi = cos^{-1}(\frac{15}{17})$

$\theta = tan^{-1}\frac{y}{x}$

The angle θ gives a tangent that doesn't exist. Analysing table of sine, cosine and tangent: θ = $\frac{\pi}{2}$

c) (√2,1,1)

$\rho = \sqrt{(\sqrt{2} )^{2}+1^{2}+1^{2}}$ = 2

$\phi = cos^{-1}(\frac{1}{2})$

$\phi$ = $\frac{\pi}{3}$

$\theta = tan^{-1}\frac{1}{\sqrt{2} }$

d) (−2√3,−2,3)

$\rho = \sqrt{(-2\sqrt{3} )^{2}+(-2)^{2}+3^{2}}$ = 5

$\phi = cos^{-1}(\frac{3}{5})$

Since x < 0, use 2nd option:

$\theta = \pi + tan^{-1}\frac{1}{\sqrt{3} }$

$\theta = \pi + \frac{\pi}{6}$

$\theta = \frac{7\pi}{6}$

Cilindrical coordinate describes a 3 dimension space: 2 distances (r and z) and 1 angle (θ). To express cartesian coordinates into cilindrical:

$r=\sqrt{x^{2}+y^{2}}$

Angle θ is the same as spherical coordinate;

z = z

Calculating:

a) (4,2,-4)

$r=\sqrt{4^{2}+2^{2}}$ = $\sqrt{20}$

$\theta = tan^{-1}\frac{1}{2}$

z = -4

b) (0, 8, 15)

$r=\sqrt{0^{2}+8^{2}}$ = 8

$\theta = \frac{\pi}{2}$

z = 15

c) (√2,1,1)

$r=\sqrt{(\sqrt{2} )^{2}+1^{2}}$ = $\sqrt{3}$

$\theta = \frac{\pi}{3}$

z = 1

d) (−2√3,−2,3)

$r=\sqrt{(-2\sqrt{3} )^{2}+(-2)^{2}}$ = 4

$\theta = \frac{7\pi}{6}$

z = 3

5 0

3 years ago

Pls look at the photo and help me! ASAP! Luv you guys <3

alexandr1967 [171]

Answer:

2 layers of cubes

Step-by-step explanation

ignore this my answer was wrong sorry

3 0

2 years ago

The population of Philadelphia in 1990 was 1,585,577. In 2010 the population was 1,526,006. What is the percent change the popul

UNO [17]

Answer:

-3.9% I.e there is decrease in the population

Step-by-step explanation:

Population @ 1990 = 1585577

Population @ 2010 = 1526006

% change =

(1526006-1585577)/1526006 × 100%

= -59571/1526006 ×100%

= -3.9%

7 0

3 years ago

Roberto decorates retangular signs. One sign is 2/3 foot long and 1/4 foot wide. Another sign is 1/2 long and 1/3 foot wide. It

PilotLPTM [1.2K]

Answer:

It'll take him 1/4 hours to decorate the two signs.

Step-by-step explanation:

In order to know how long Roberto will take to decorate all the signs we need to find their surface area, since they're rectangular their area is given by the product of their dimensions.

First sign:

area1 = (2/3)*(1/4) = 2/12 = 1/6 foot²

Second sign:

area2 = (1/2)*(1/3) = 1/6 foot²

The total area he has to paint is the sum of their individual areas, so we have:

total area = area1 + area2 = 1/6 + 1/6 = 2/6 = 1/3 foot²

To find out how long he'll take to decorate this area we can use a rule of three as shown bellow:

3/4 hour -> 1 foot²

x hour -> 1/3 foot²

x = (3/4)*(1/3) = 1/4 hours

3 0

3 years ago