# Thread: express in terms of x

1. ## express in terms of x

Express x in terms of the other variables in the picture
a.)first problem
b.)second problem

sry for sucky graphics cause i had it on a page and didnt know how to put it on the computer so used paint

2. Originally Posted by saar4ever
Express x in terms of the other variables in the picture
a.)first problem
b.)second problem

sry for sucky graphics cause i had it on a page and didnt know how to put it on the computer so used paint

for the first one , by similar triangles ..

t/h=(x+t)/r

Then make x the subject .

i will let you figure out the second one

3. could u still help me out on the second one cause i dont see how u do similair triangles and dont remember which therom relates x h r and t

4. Originally Posted by saar4ever
could u still help me out on the second one cause i dont see how u do similair triangles and dont remember which therom relates x h r and t
Ok , the vertical height is missing right, so you can use the phythogaros theorem to get $\sqrt{x^2-t^2}$

So again by similar triangles :

$\frac{r}{h}=\frac{x}{\sqrt{x^2-t^2}}$

$xh=r\sqrt{x^2-t^2}$

$x^2h^2=r^2x^2-r^2t^2$

$x^2(r^2-h^2)=r^2t^2$

can take it from here ?

5. thanks just finished the problem