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3 years ago

Cara is 14 years old . This is twice as old as her brother . How old is her brother

Mathematics

2 answers:

Alenkinab [10]3 years ago

6 0

Cara's brother is 7 years old.

14 is twice as much as 7 (7 * 2 = 14).

Gre4nikov [31]3 years ago

4 0

Answer:

Step-by-step explanation:

If Cara is twice the age of her brother,

divide 14/2

7, her brother is 7

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A cone has a diameter of 7.5 ft and a height of 4.25 ft. What is the volume of the cone to the nearest tenth? Use 3.14 for π.

leva [86]

Answer:

The volume of a cone is $62.5\ \text{feet}^3$ .

Step-by-step explanation:

We have,

Diameter of a cone is 7.5 ft

Radius of a cone is 3.75 ft

Height of the cone is 4.25 ft

It is required to find the volume of the cone. The formula of the volume of cone is given by :

$V=\dfrac{1}{3}\pi r^2 h\\\\V=\dfrac{1}{3}\times 3.14\times (3.75)^2\times 4.25\\\\V=62.55\ \text{feet}^3$

So, the volume of a cone is $62.5\ \text{feet}^3$ .

3 0

4 years ago

What is the surface area of a cylinder that is 5 centimeters high and has a diameter of 1.5 centimeters?

olchik [2.2K]

The surface area of cylinder is 8.625 $\pi$ $cm^{2}$ , if the cylinder has 5 centimeters high and 1.5 cm of diameter.

Step-by-step explanation:

The given is,

Cylinder has a 5 centimeters height

Diameter of the cylinder is 1.5 centimeters

Step:1

Formula for the surface area of cylinder is,

$A=2\pi r h + 2\pi r^{2}$ ......................................(1)

Where,

h - Height of cylinder

r - Radius of cylinder

From the values of h and r,

$r=\frac{d}{2}$

= $\frac{1.5}{2}$

r = 0.75 cm

From the formula,

= ( 2 × $\pi$ × 0.75 × 5 ) + ( 2 × $\pi$ × $0.75^{2}$ )

= ( 7.5 $\pi$ ) + ( 1.125 $\pi$ )

A = 8.625 $\pi$ $cm^{2}$

Result:

The surface area of cylinder is 8.625 $\pi$ $cm^{2}$ , if the cylinder has 5 centimeters high and 1.5 cm of diameter.

3 0

4 years ago

Which equation represents line shown in the accompanying<br> diagram?

Sergeu [11.5K]

I am pretty sure it’s c because you go up 4 and over 3 to the right so that would be plus 3

5 0

3 years ago

the initial vertical velocity of a rocket shot straight up is 42 meters per second. How long does it take for the rocket to retu

Snowcat [4.5K]

It takes 4.3 seconds for the rocket to return to earth.

The equation is:
$0=-9.8t^2+v_0t+h_0$
where -9.8m/sec² is the acceleration due to gravity, v₀ is the initial velocity, and h₀ is the initial height. We will go from the assumption that the rocket is launched from the ground, so h₀=0, and we are told that the initial velocity, v₀, is 42. This gives us:

$0=-9.8t^2+42t$

We will use the quadratic formula to solve this. The quadratic formula is:
$x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$

Plugging in our information we have:
$t=\frac{-42\pm \sqrt{42^2-4(-9.8)(0)}}{2(-9.8)}
\\
\\=\frac{-42\pm \sqrt{1764-0}}{-19.6}
\\
\\=\frac{-42\pm \sqrt{1764}}{-19.6}
\\
\\=\frac{-42\pm 42}{-19.6}=\frac{-42-42}{-19.6} \text{ or } \frac{-42+42}{-19.6}
\\
\\=\frac{-84}{-19.6}\text{ or }\frac{0}{-19.6}
\\
\\=4.3\text{ or }0$

x=0 is when the rocket is launched; x=4.3 is when the rocket lands.

8 0

3 years ago

Are the two expressions equivalent 5(3x+8) 8x+8 when x=10

Brums [2.3K]

Answer:no

Step-by-step explanation:

5(3(10)+8)

5(30+8)

5(38)=190

8(10)+8

80+8

88≠190 so no

7 0

3 years ago

Read 2 more answers