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Mathematics 8 Online
OpenStudy (anonymous):

How do I find a and b?

OpenStudy (anonymous):

I don't just want an answer... I need an explanation ...

OpenStudy (oaktree):

By Pythagorean Theorem on the smallest right triangle, \[a^2+20^2=b^2\] However, using the biggest triangle, we have that \[29^2b^2=(21+a)^2\] This is now a solvable system of equations.

OpenStudy (oaktree):

Alternatively, you can make a proportion using the fact that all of the right triangles are similar to one another.

OpenStudy (anonymous):

That was really confusing.. @OakTree

OpenStudy (oaktree):

What was? The first or second response?

OpenStudy (anonymous):

Both of them...

OpenStudy (anonymous):

@OakTree

OpenStudy (oaktree):

For the first one, you can solve the system. Have you solved systems before?

OpenStudy (anonymous):

No... I went from Algebra Support to Geometry.....

OpenStudy (oaktree):

Oh! I see the mistake. In the first response, second formula, it should be 20^2 + B^2. Sorry.

OpenStudy (oaktree):

Anyway, a system is when you have n variables and n equations, which allows you to solve for all of the variables.

OpenStudy (oaktree):

You solve it by, in this one, taking the value for b^2 in the first equation and plugging it into the second equation. Because, b^2 is the same as a^2 + 20^2, so you can exchange them freely.

OpenStudy (anonymous):

how did you get them squared???

OpenStudy (oaktree):

You get\[29^2 + (a^2 + 20^2) = (21+a)^2\]

OpenStudy (oaktree):

This is now an equation with one variable, which you should be able to solve pretty easily.

OpenStudy (oaktree):

Oh, they're squared from the pythagorean theorem. You know, a^2+b^2=c^2?

OpenStudy (anonymous):

oh okay!! I'm gonna try to solve that one and send you what I got as an answer/

OpenStudy (oaktree):

|dw:1360200275840:dw|

OpenStudy (anonymous):

Yeah I can't even solve that....

OpenStudy (oaktree):

You've never solved a quadratic equation?

OpenStudy (anonymous):

not that i remember

OpenStudy (anonymous):

i thought i was supposed to put a/21=b/29?

OpenStudy (oaktree):

That was the second solution. But then what do you do? You need a second equation, which you can only get from the Pythagorean Theorem.

OpenStudy (anonymous):

then cross multiply?

OpenStudy (anonymous):

this is so confusing.

OpenStudy (oaktree):

You need to talk to your teacher. I can't teach you quadratics over OpenStudy...it's too complicated.

OpenStudy (oaktree):

You're missing a lot of basic skills.

OpenStudy (anonymous):

okay. thank you for the help.

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