1. ## co ordinate geometry

can anyone help??
got this question,,
The points ABC have co ordinates (2, 1) (b,3) and (5,5) where b>3
and angle ABC=90degrees ??
I know the answer just have no idea how to work it out.

2. (slope of AB)(slope of BC) = -1

3. In a right triangle $\displaystyle a^2 + b^2 = c^2$.
So $\displaystyle (b-2)^2 +(3-1)^2 + (b-5)^2 + (3-5)^2 = (5-2)^2 + (5-1)^2$

4. does that make b= 6
cause i justtried and got some strange answer sorry i'm a bit rubbish at this
Originally Posted by Plato
In a right triangle $\displaystyle a^2 + b^2 = c^2$.
So $\displaystyle (b-2)^2 +(3-1)^2 + (b-5)^2 + (3-5)^2 = (5-2)^2 + (5-1)^2$