All categories

3 years ago

A solid cylinder of radius 7cm is 10cm long.find it's total surface area

Mathematics

2 answers:

Anton [14]3 years ago

7 0

Answer:

C. 238π cm^3.

Step-by-step explanation:

Surface area = 2 * area of the circular ends + area of the curved length

= 2π r^2 + 2π r* l

= 2 π 7^2 + 2π 7 * 10

= 98π + 140π

= 238π cm^3.

Talja [164]3 years ago

6 0

Answer:

c. 238πcm3

Step-by-step explanation:

Total surface area =

2pirh + 2pir^2

Given radius r = 7cm and

Height h = 10cm

Total surface area = 2 x pi x 7 x 10 + 2 x pi x (7)^2

140pi + 2 x pi x 49

140pi + 98pi

238pi cm^3

You might be interested in

Find thd <img src="https://tex.z-dn.net/?f=%5Cfrac%7Bdy%7D%7Bdx%7D" id="TexFormula1" title="\frac{dy}{dx}" alt="\frac{dy}{dx}" a

NARA [144]

$x^3y^2+\sin(x\ln y)+e^{xy}=0$

Differentiate both sides, treating $y$ as a function of $x$ . Let's take it one term at a time.

Power, product and chain rules:

$\dfrac{\mathrm d(x^3y^2)}{\mathrm dx}=\dfrac{\mathrm d(x^3)}{\mathrm dx}y^2+x^3\dfrac{\mathrm d(y^2)}{\mathrm dx}$

$=3x^2y^2+x^3(2y)\dfrac{\mathrm dy}{\mathrm dx}$

$=3x^2y^2+6x^3y\dfrac{\mathrm dy}{\mathrm dx}$

Product and chain rules:

$\dfrac{\mathrm d(\sin(x\ln y)}{\mathrm dx}=\cos(x\ln y)\dfrac{\mathrm d(x\ln y)}{\mathrm dx}$

$=\cos(x\ln y)\left(\dfrac{\mathrm d(x)}{\mathrm dx}\ln y+x\dfrac{\mathrm d(\ln y)}{\mathrm dx}\right)$

$=\cos(x\ln y)\left(\ln y+\dfrac1y\dfrac{\mathrm dy}{\mathrm dx}\right)$

$=\cos(x\ln y)\ln y+\dfrac{\cos(x\ln y)}y\dfrac{\mathrm dy}{\mathrm dx}$

Product and chain rules:

$\dfrac{\mathrm d(e^{xy})}{\mathrm dx}=e^{xy}\dfrac{\mathrm d(xy)}{\mathrm dx}$

$=e^{xy}\left(\dfrac{\mathrm d(x)}{\mathrm dx}y+x\dfrac{\mathrm d(y)}{\mathrm dx}\right)$

$=e^{xy}\left(y+x\dfrac{\mathrm dy}{\mathrm dx}\right)$

$=ye^{xy}+xe^{xy}\dfrac{\mathrm dy}{\mathrm dx}$

The derivative of 0 is, of course, 0. So we have, upon differentiating everything,

$3x^2y^2+6x^3y\dfrac{\mathrm dy}{\mathrm dx}+\cos(x\ln y)\ln y+\dfrac{\cos(x\ln y)}y\dfrac{\mathrm dy}{\mathrm dx}+ye^{xy}+xe^{xy}\dfrac{\mathrm dy}{\mathrm dx}=0$

Isolate the derivative, and solve for it:

$\left(6x^3y+\dfrac{\cos(x\ln y)}y+xe^{xy}\right)\dfrac{\mathrm dy}{\mathrm dx}=-\left(3x^2y^2+\cos(x\ln y)\ln y-ye^{xy}\right)$

$\dfrac{\mathrm dy}{\mathrm dx}=-\dfrac{3x^2y^2+\cos(x\ln y)\ln y-ye^{xy}}{6x^3y+\frac{\cos(x\ln y)}y+xe^{xy}}$

(See comment below; all the 6s should be 2s)

We can simplify this a bit by multiplying the numerator and denominator by $y$ to get rid of that fraction in the denominator.

$\dfrac{\mathrm dy}{\mathrm dx}=-\dfrac{3x^2y^3+y\cos(x\ln y)\ln y-y^2e^{xy}}{6x^3y^2+\cos(x\ln y)+xye^{xy}}$

3 0

3 years ago

I need some help with this

masya89 [10]

Answer:

A, C, D

Step-by-step explanation:

Consider triangles NKL and NML. These triangles are right triangles, because

$m\angle K=m\angle M=90^{\circ}$

In these right triangles:

$\overline{NL}\cong \overline {NL}$ - reflexive property;
$\angle KLN\cong \angle MLN$ - given

Thus, triangles NKL and NML by HA postulate. Congruent triangles have congruent corresponding parts, so

$\overline{KN}\cong \overline{NM}\\ \\\overline{KL}\cong \overline{LM}\ [\text{option D is true}]$

Since

$\overline{KN}\cong \overline{NM},$

then

$7x-4=5x+12\\ \\7x-5x=12+4\\ \\2x=16\\ \\x=8\ [\text{option A is true}]\\ \\MN=KN=7\cdot 8-4=56-4=52\ [\text{option C is true}]$

Option B is false, because KN=52 units.

Option E is false, because LN is congruent KN, not LM

4 0

3 years ago

1/2 of a bag of candy is skittles, 1/4 is m and m's, and 3/4 of the rest of it are life savers. The rest are sour patch kids. Wh

m_a_m_a [10]

Answer:

6.25%

Step-by-step explanation:

Total = 1 ; as a decimal

1/2 = skittles

1/4 = M&Ms

Skittles +M&Ms = 1/2 + 1/4 = 3/4

Remainder = 1 - $\frac{3}{4}$

Remainder = $\frac{1}{4}$

Sour patch = $\frac{1}{4} *\frac{1}{4} =\frac{1}{16}$

As a percentage , multiply 1/16 by 100 and it becomes 6.25%

5 0

3 years ago

Together, two apples have 1/5 gram of fat. How many apples have a total of 4 grams of fat?

4vir4ik [10]

20 apples

1/5=0.2

0.2×20=4

4 0

3 years ago

Read 2 more answers

Dane says that the answer to the problem 4 to the 6th power times 4 to the 3th power is 16 to the 9th power. What was his mistak

lesya [120]

Step-by-step explanation:

his mistake was that he didnt follow the rules of the order of operations and he multiplied 4 by 4 and just added the third power and the 6th power getting the wrong answer

hope this helps:) good luck

8 0

3 years ago