Step 1: Understanding shapes
A circle is a two-dimensional figure in which all points are equidistant from the center.
Step 2: Evaluating the given shapes
(A) \Circle $\Rightarrow$ Correct shape of a circle
(B) \Square $\Rightarrow$ Four equal sides, not a circle
(C) \triangle $\Rightarrow$ Three-sided polygon
(D) None of these $\Rightarrow$ Incorrect, as option (A) is correct
\[
\boxed{\text{Correct Answer: (A) Circle}}
\]
Find the unknown frequency if 24 is the median of the following frequency distribution:
\[\begin{array}{|c|c|c|c|c|c|} \hline \text{Class-interval} & 0-10 & 10-20 & 20-30 & 30-40 & 40-50 \\ \hline \text{Frequency} & 5 & 25 & 25 & \text{$p$} & 7 \\ \hline \end{array}\]
Two concentric circles are of radii $8\ \text{cm}$ and $5\ \text{cm}$. Find the length of the chord of the larger circle which touches (is tangent to) the smaller circle.