Find out the missing item x of the following distribution, where arithmetic mean $\left(\overline{X}\right)$ is 11.37

$\begin{array}{cccccccc}X& 5& 7& X& 11& 13& 16& 20\\ \text{Frequency (f)}& 2& 4& 29& 54& 11& 8& 4\end{array}$

Degree of a constant polynomial is

In given figure, from a rectangular region ABCD with AB = 20 cm, a right triangle AED with AE = 9 cm and DE = 12 cm, is cut off. On the other end, taking BC as diameter, a semicircle is added on outside the region. Find the area of the shaded region. (Use $\pi =22/7$)

From an external point P, two tangents, PA and PB are drawn to a circle with centre O. At one point E on the circle tangent is drawn which intersects PA and PB at C and D, respectively. If PA $=$ 10 cm, find the the perimeter of the $\Delta PCD$.

If one zero of the polynomial$(a^2+9)x^2+13x+6a$ is reciprocal of the other, find the value of a

If $a,b,c,d$ are in GP, then

Degree of a constant polynomial is

In given figure, from a rectangular region ABCD with AB = 20 cm, a right triangle AED with AE = 9 cm and DE = 12 cm, is cut off. On the other end, taking BC as diameter, a semicircle is added on outside the region. Find the area of the shaded region. (Use $\pi =22/7$)

From an external point P, two tangents, PA and PB are drawn to a circle with centre O. At one point E on the circle tangent is drawn which intersects PA and PB at C and D, respectively. If PA $=$ 10 cm, find the the perimeter of the $\Delta PCD$.