What is the best approximation of the surface area of this right cone?

Mathematics

1 answer:

inn [45]3 years ago

8 0

$\bf \textit{total surface area of a cone}\\\\
s=\pi r\sqrt{r^2+h^2}+\pi r^2\quad 
\begin{cases}
r=radius\\
h=height\\
-----\\
r=12\\
h=9
\end{cases}
\\\\\\
s=\pi (12)\sqrt{12^2+9^2}+\pi (12^2)\implies s=12\pi \sqrt{225}+144\pi 
\\\\\\
s=12\pi (15)+144\pi \implies s=180\pi +144\pi \implies s=324\pi$

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Mr. Kohl has a breaker containing n milliliters of solution to distribute to the students in his chemistry class. If he gives ea

77julia77 [94]

Answer:

There were 26 students in his class and the teacher had 83 ml of the solution.

Step-by-step explanation:

Mr. Kohl has a "x" amount of solution, if he divides it by the number of students "n" he'll give each student 3 milliliters and have a left over of 5 milliliters. If the amount of solution Mr. Kohl had was "x + 21" then he'd be able to give each student 4 milliliters of the solution. From these informations we have:

x = 3*n + 5

(x + 21)/n = 4

x + 21 = 4*n

x = 4*n - 21

Now that we have two equations and two variables we can solve the system of equations, as seen bellow:

3*n + 5 = 4*n - 21

3*n - 4*n = -21 - 5

-n = -26

n = 26

x = 4*26 - 21 = 83 ml

There were 26 students in his class and the teacher had 83 ml of the solution.

3 0