Algebra

I don't understand how to do this problems: Solve for the variable r, C=2PIr (PI is the pi symbol thing then r is next to it) and this problem solve for the variable l, S=B+1/2Pl please help :)

When you solve for a variable, you want that "letter" on one side and everything else on the other. If we have C = 2*pi*r, then
r = C/(2*pi)

I don't get your second equation. Is that 1/2*P or 1/2*P*I. If the latter than I = .....just as I did the first one.

1) C=2plr so r = C/2pl

2)S=B+1/2Pl so 1 = 2pi(S-B)

thank you for the help! :) but for the second equation it's one half right beside a capital P then a lower case l i do not understand how to solve it

Do you understand what I did for the first one?
C = 2*pi*r
Divide both sides by 2*pi so it is
C/2*pi = 2*pi*r/2*pi
On the right side, now, the 2*pi cancels leaving just r; therefore.
C/(2*pi) = r.

For the second one, my l on the computer looks like the letter 1 so I will make it a capital I.
We have S = B + (1/2)PI
since is is easier to handle numbers rather than fractions, we multiply everyting by 2.
2*S = 2*B + 2*(1/2)*PI
on the right side the 2(1/2) = 1 and the equation is now
2S = 2B + PI
Next, let's subtract 2B from both sides.
2S - 2B = 2B -2B + PI
The 2B on the right side adds out so we are left with
2S - 2B = PI. We have effectively just moved the 2B from the right side to the left side.
Now we solve for I. Probably you can do the rest. Post your work if you want us to check it. But if you don't understand any of the other steps, repost and explain exactly what you don't understand.

To slove for somthing is to get it all by itself on one side of the = sign.

Do the same thing to both sides of the equal sign so the equation stays true.

For example: solve for A, A+B=C
to get A by itself, do A+B-B=C-B
when you do the math A=C-B is the result.

In your first question, you need to move the 2Pi to the other side by deviding both sides by 2Pi.

C=(2Pi)r
C/(2Pi)=(2Pi)r/(2Pi)
do the math, and,
C/(2Pi)=r

the second question, do you mean
solve for I? As in S=B+(1/2P)I ?

or did you mean solve for Pi? S=B+(1/2Pi)?

How did the symbol for pi come about

  1. 👍 0
  2. 👎 0
  3. 👁 245
asked by Avalon

Respond to this Question

First Name

Your Response

Similar Questions

  1. Algebra again

    I don't understand how to do this problems: Solve for the variable r, C=2PIr (PI is the pi symbol thing then r is next to it) and this problem solve for the variable l, S=B+1/2Pl I know this is the same question, but I somewhat

    asked by Avalon on November 18, 2006
  2. Algebra

    There are 4 problems that I don't understand how to solve so, please help me. A numerical explanation with words explanation would be nice. Thank you tutors. Rewrite each equation so it is in the form ax + b = c or x + d/e = f,

    asked by anon on December 9, 2015
  3. Calculus

    A cylindrical drum is made to hold exactly 1m^3 in its interior. Assume that the material for the top and the bottom costs $20 per m^2, while that for the side costs $10 per m^2. Determine the radius of the drum that minimizes the

    asked by Fredrique on December 9, 2006
  4. math

    how would I solve 10=7-m? I don't understand how to find the variable and I use flowchart!none of my math books show me how! so how can I solve problems like these?

    asked by Emi on January 11, 2013
  5. Math

    I have some problems that I don't understand. Please help me. Solve the formula for the specified variable. s=2ðrh + 2ðr^2 for h f= (9/5)c+32 for c A=P(1+nr) for r for H i don't know what that notation is so I'll leave that

    asked by Samantha on August 18, 2007
  6. Math ----- Calculus -- Word Problem

    A cylinder is to be constructed so that its height plus the perimeter of its base must equal to 2pi cm. Find the ratio of the radius of this cylinder to its height if it is to have a maximum volume. My work: SA = 2pirh + 2pir^2

    asked by Anonymous on June 3, 2008
  7. math

    there's a question that I don't understand and the direction says that 'solve problems as combination integer problems.remember to rewrite all double sign problems as combination problems before solving' and here's a question 50-

    asked by allie on January 22, 2008
  8. Pre-Algebra

    Can someone please show me how to solve these problems step-by-step so that I can understand how to do them? 1.Use inverse operations to write a related inequality and solve for the variable: d/6 < 12 2.Use inverse operations to

    asked by mysterychicken on May 1, 2009
  9. calc

    the volume of a cylindrical tin can with a top and a bottom is to be 16*pi cubic inces. if a minimum amont of tin is to be used to construct the can, what must be the height, in inches, of the can? volume of cyliner is pi*r^2*h do

    asked by david on December 8, 2006
  10. Physics

    I don't understand anything about the centripital force and torque please HELP me to understand hoe to solve problems relsted to this topics,

    asked by John on August 29, 2011

More Similar Questions