Step 1: Definition of parallel lines
Parallel lines are lines in the same plane that never meet, no matter how far they are extended.
They are always the same distance apart.
Step 2: Eliminate incorrect options
- (B): Lines that intersect are not parallel.
- (C): Zig-zag lines change direction — not straight — hence not parallel.
- (D): A single straight line is not sufficient; we need a pair to be called parallel.
\[ $\Rightarrow$ \text{Only option (A) satisfies the condition for parallel lines.}
\]
\[
\boxed{\text{Correct Answer: (A) Two straight lines which cannot intersect each other}}
\]
In the given figure, the value of \( \angle DEC \) is:
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.