In $∆PQR$, $P{Q}^2+Q{R}^2=P{R}^2$ and $PR=2QR$. Write the measures of the angles of the triangle.

$ABCD$ is a rectangle. $P$ is the midpoint of $BC$, $AP=8 \mathrm{cm}$. Find the sides $AB$ and $BC$

$ABC$ is an equilateral triangle, $AB=3 \mathrm{cm}, \mathrm{AD}=1 \mathrm{cm}$ and  $ED\perp AB$. Find the perimeter of $BCED$ 

In $∆PQR, PT\perp QR$, $PQ=10 \mathrm{cm}$, $QT=6 \mathrm{cm}$, $TR=15 \mathrm{cm}$. Find the value of $\sin x+\tan y$