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Mathematics 17 Online
OpenStudy (compassionate):

Trying to find AB and BC.

OpenStudy (compassionate):

I tried a few methods but none seem to work.

OpenStudy (anonymous):

??

OpenStudy (compassionate):

Just need some assistance on the right method. I used tan(30) = BC/5sqrt(3) to find BC, Then I found DB to use Tan(45) = AB/DB to find AB, but when I subtract BC from AB, it seems to be wrong. I tried working it out again and got something different.

ganeshie8 (ganeshie8):

are u able to find BC ?

ganeshie8 (ganeshie8):

the fastest way to do this is using the special triangles : http://www.mathwarehouse.com/geometry/triangles/right-triangles/images/picture-30-60-90-special-right-triangle.png

ganeshie8 (ganeshie8):

Just by looking at the diagram, you can say that \(BC = 5\)

OpenStudy (compassionate):

\[\tan(30)= \frac{ BC }{ 5 \sqrt3 } = 5\] \[Sin(30) = \frac{ 5 }{ BD } = \frac{ 5 }{0.5 } = 10; BD = 10\] \[\tan(45) = \frac{ AB }{ 10 } = 1 * 10 = AB; AB = 10\] So then I subtract BC from AB because I am trying to find the measurements of JUST AB, and I get 5. However, 5 isn't a solution. So where did I go wrong?

ganeshie8 (ganeshie8):

mistake !

ganeshie8 (ganeshie8):

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