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2 years ago

Find the surface area.

Mathematics

1 answer:

Marysya12 [62]2 years ago

8 0

let's notice, this is a Cube, namely all equal sides, and mind you it has 6 sides, Check the picture below.

$\stackrel{\textit{area of all 6 sides}}{6(9\cdot 9)\implies 486}$

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Work out the value of z, given that x+y=42 and x/13=y/8=z/9.

Andru [333]

Answer:

z = 18

x = 26 and y = 16

Step-by-step explanation:

Given:

$x + y = 42$

$\dfrac{x}{13}=\dfrac{y}{8}=\dfrac{z}{9}$

Rewrite $x + y = 42$ to make $y$ the subject:

$\implies y=42-x$

Substitute this into $\dfrac{x}{13}=\dfrac{y}{8}$ :

$\implies \dfrac{x}{13}=\dfrac{42-x}{8}$

Cross multiply:

$\implies 8x=13(42-x)$

$\implies 8x=546-13x$

$\implies 21x=546$

$\implies x=26$

Substitute found value of x into $x + y = 42$ and solve for y:

$\implies 26 + y = 42$

$\implies y=16$

Substitute found value of y into $\dfrac{y}{8}=\dfrac{z}{9}$ and solve for z:

$\implies \dfrac{16}{8}=\dfrac{z}{9}\\\\\implies 2=\dfrac{z}{9}\\\\\implies 18=z$

4 0

2 years ago

According to a study, 15 out of 50 adults have allergies. What percentage of adults do not have allergies?

love history [14]

Answer:

70% of adults do not have allergies.

Step-by-step explanation:

It states that 35 out of 50 adults do not have allergies. If we turn this into a fraction (35/50), we can then multiply the denominator by 2 to make it 100. We would then also multiply the numerator by 2.

35 x 2 =70

70/100 = .7

.7 is just the decimal form of 70%

3 0

3 years ago

cylinder has a height of h inches and a diameter of 3 inches. What expression gives the volume of the cylinder in cubic inches?

pashok25 [27]

Answer:

The expression that gives the volume of the cylinder in cubic inches is $V=\frac{9\pi h}{4} \:in^3$ .

Step-by-step explanation:

The base of a cylinder is a circle, the area of that circle is given by the formula:

area = $\pi r^2$

Multiplying by the height $h$ we get that the volume of a cylinder is

$V=\pi r^2h$

where:

π = Pi

r = the radius of the circular end of the cylinder

h = height of the cylinder

We know that the cylinder has a height of h inches and a diameter of 3 inches.

The radius of a circle is half the diameter and the volume is:

$V=\pi (\frac{3}{2}) ^2h=\frac{9\pi h}{4} \:in^3$

7 0

3 years ago

12. A is the point with coordinates (1,3)

Ghella [55]

Answer:

line L is not parallel to AB

Step-by-step explanation:

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

Given

3y = 4 - 2x ( divide terms by 3 )

y = $\frac{4}{3}$ - $\frac{2}{3}$ x ← in slope- intercept form

with slope m = - $\frac{2}{3}$

Calculate slope of AB using the slope formula

m = $\frac{y_{2}-y_{1} }{x_{2}-x_{1} }$

with (x₁, y₁ ) = A(1, 3) and (x₂, y₂ ) = B(- 2, - 1)

$m_{AB}$ = $\frac{-1-3}{-2-1}$ = $\frac{-4}{-3}$ = $\frac{4}{3}$

Parallel lines have equal slopes

Since the slopes are not equal then the lines are not parallel

5 0

2 years ago

A $1200 investment is made. How much should be invested at 15% and how much at 8% so that the total return on the entire investm

Margaret [11]

Answer:

The amount invested at 15% = $257.14

The amount invested at 8% = $942.86

Step-by-step explanation:

Let the amount invested at:

15% = a

8% = b

Total invesment = $1200

Hence:

a + b= $1200....... Equation 1

a = 1200 - b

15% × a + 8% × b = 9.5% × 1200

0.15a + 0.08b = 0.095 × 1200

0.15a + 0.08b = 114..... Equation 2

We substitute 1200 - b for a in Equation 2

0.15(1200 - b) + 0.08b = 114

180 - 0.15b + 0.08b = 114

- 0.15b + 0.08b = 114 - 180

- 0.07b = - 66

b = -66/-0.07

b = $942.85714286

Approximately = $942.86

Note that:a = 1200 - b

a = $1200 - $942.86

a = $257.14

5 0

2 years ago

Find the surface area. ​

Find the surface area.