Step 1: Understanding the Earth Summit
The first International Earth Summit is officially known as the United Nations Conference on Environment and Development (UNCED). It was a major United Nations conference held in 1992 to discuss global environmental and sustainable development issues.
Step 2: Venue of the summit
The conference was held in Rio de Janeiro, Brazil, from 3rd to 14th June, 1992. Hence, it is also called the Rio Summit.
Step 3: Significance
At the Rio Summit, important agreements like Agenda 21, the Convention on Biological Diversity, and the Framework Convention on Climate Change (UNFCCC) were signed.
Step 4: Conclusion
Thus, the correct answer is:
\[
\boxed{\text{Rio De Janeiro, Brazil}}
\]
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.