Thread: Rotation of triangle

Hi

I am finding this question tough (attached), I think I may have stumbled on the answer but could do with some confirmation I'm on the right path.

Right, so far I have found the length using Phythagoras.

Now I need to determine , and

This is where I am stuck. It is not a right angled triangle so can I use SOHCAHTOA?
Never the less I have attempted this way and got







Which all give the same answer incidentally - is this the right approach or am I off in the completely wrong direction?

I get the last part about the two line notation, but am not sure what values to use for x and y.


Please help.

Thanks

Originally Posted by Ian1779

Hi

I am finding this question tough (attached), I think I may have stumbled on the answer but could do with some confirmation I'm on the right path.

Right, so far I have found the length using Phythagoras.

Now I need to determine , and

This is where I am stuck. It is not a right angled triangle so can I use SOHCAHTOA?
Never the less I have attempted this way and got







Which all give the same answer incidentally - is this the right approach or am I off in the completely wrong direction?

I get the last part about the two line notation, but am not sure what values to use for x and y.


Please help.

Thanks

After the rotation the side B''C'' has the slope m = 0. Calculate the the slope of BC (2-point-formula of a straight line) which is equal of the tangens of the angle of rotation:



That means you have to rotate the triangle by an angles whose tangens is

I'm not quite sure what is meant by the two-line notation. The angle in question is included by the lines with the equations:

Thanks so much. The drawing helped even more so I could visualise it better.