Question : The area of a circle is the same as the area of a square. What is the ratio of the diameter of the circle and the diagonal of the square?
Option 1: $1:\sqrt{\pi }$
Option 2: $2:\sqrt{\pi }$
Option 3: $\sqrt{2}:\sqrt{\pi }$
Option 4: $1:{\pi }$
Correct Answer: $\sqrt{2}:\sqrt{\pi }$
Solution : Let the area of a circle $=\pi r^2$ where $r$ is the radius of the circle. The diameter of the circle is $2r$. Let the area of a square $=a^2$ where $a$ is the side length of the square. The diagonal ($d$) of the square $=a\sqrt{2}$ Given that the area of the circle is equal to the area of the square. $\pi r^2 = a^2$ ⇒ $a = r\sqrt{\pi}$ Substituting this into the formula for the diagonal of the square. $d = a\sqrt{2} = r\sqrt{2\pi}$ The required ratio $=\frac{2r}{r\sqrt{2\pi}} = \frac{2}{\sqrt{2\pi}} = \frac{\sqrt{2}}{\sqrt{\pi}}$ Hence, the correct answer is $\sqrt{2}:\sqrt{\pi }$.
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Question : If the perimeter of a square is $80\;\mathrm{cm}$, then what is the diagonal (in $\mathrm{cm}$) of the square?
Option 1: $20\sqrt{2}$
Option 2: $40\sqrt{2}$
Option 3: $80\sqrt{2}$
Option 4: $20$
Question : If the length of a side of the square is equal to that of the diameter of a circle, then the ratio of the area of the square and that of the circle is:
Option 1: 14 : 11
Option 2: 7 : 11
Option 3: 11 : 14
Option 4: 11 : 7
Question : If the perimeter of a square is $44\;\mathrm{cm}$, what is the diagonal (in $\mathrm{cm}$) of the square?
Option 1: $11\sqrt{2}$
Option 2: $2\sqrt{11}$
Option 3: $11$
Option 4: $44\sqrt{2}$
Question : A sphere and another solid hemisphere have the same surface area. The ratio of their volumes is:
Option 1: $2 \sqrt{3}: 8$
Option 2: $3 \sqrt{3}: 8$
Option 3: $3 \sqrt{3}: 4$
Option 4: $\sqrt{3}: 4$
Question : The diameter of a hemisphere is equal to the diagonal of a rectangle of length 4 cm and breadth 3 cm. Find the total surface area (in cm²) of the hemisphere.
Option 1: $25 \pi$
Option 2: $\frac{75 \pi}{4}$
Option 3: $\frac{50 \pi}{4}$
Option 4: $\frac{25 \pi}{4}$
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