standard_description: Prove the Pythagorean identity sin^(2)(θ) + cos^(2)(θ) = 1 and use it to find sin(θ), cos(θ),or tan(θ) given sin(θ), cos(θ), or tan(θ) and the quadrant of the angle.
problem_activity: Task
Below is a picture of a triangle $ABC$ on the coordinate grid.  The red lines are parallel to $\overleftrightarrow{BC}$:
[IMG]
Suppose $P = (1.2,1.6)$, $Q = (2,4)$, and $R = (2.4,5.2)$.
Find the coordinates of the points $u$, $v$, and $w$.


aligns: no