Heights of $\displaystyle 50$ students of class X of a school are recorded and following data is obtained :

Height (in cm) :	$\displaystyle 130$-$\displaystyle 135$	$\displaystyle 135$-$\displaystyle 140$	$\displaystyle 140$-$\displaystyle 145$	$\displaystyle 145$-$\displaystyle 150$	$\displaystyle 150$-$\displaystyle 155$	$\displaystyle 155$-$\displaystyle 160$
Number of Students :	$\displaystyle 4$	$\displaystyle 11$	$\displaystyle 12$	$\displaystyle 7$	$\displaystyle 10$	$\displaystyle 6$

Find the median height of the students.

$\displaystyle 7$ cm is melted to form ' n ' number of solid spheres of radii $\displaystyle \overline{2} \mathrm{~cm}$ each. Find the value of n. \[\begin{array}{l} n \times \frac{4}{3} \times \frac{22}{7} \times\left(\frac{7}{2}\right)^{3}=11 \times(7)^{2} \\ \Rightarrow n=3 \end{array} \]In Fig. $\displaystyle 1$, AB is diameter of a circle centered at $\displaystyle \mathrm{O} . \mathrm{BC}$ is tangent to the circle at B . If OP bisects the chord AD and $\displaystyle \angle \mathrm{AOP}=60^{\circ}$, then find $\displaystyle \mathrm{m} \angle \mathrm{C}$.Fig. $\displaystyle 1$ \[\begin{array}{c} \because A P=P D \Rightarrow O P \perp A D \\ \therefore \angle O A P=30^{\circ} \end{array} \]Also $\displaystyle \angle A B C=90^{\circ}$ \[\Rightarrow \angle C=60^{\circ} \]Or In Fig. $\displaystyle 2$, XAY is a tangent to the circle centered at O . If $\displaystyle \angle \mathrm{ABO}=40^{\circ}$, then find $\displaystyle \mathrm{m} \angle \mathrm{BAY}$ and $\displaystyle \mathrm{m} \angle \mathrm{AOB}$.Fig. $\displaystyle 2$ \[\begin{array}{l} O A=O B \Rightarrow \angle O A B=40^{\circ} \\ O A \perp A Y \Rightarrow \angle B A Y=50^{\circ} \\ \quad \angle A O B=180^{\circ}-80^{\circ}=100^{\circ} \end{array} \]