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Question

A hexagon is drawn inside a circle with a radius of 21 cm. Determine the approximate area of the hexagon.

This question was previously asked in
SSC CGL 2025 Tier 1 Question Paper (25-Sep-2025) (Shift 3)
The correct answer is
1145 $cm^2$

Hexagon Area Calculation

The problem asks for the approximate area of a regular hexagon inscribed within a circle. The radius of the circle is given as 21 cm.

Relating Hexagon to Circle

A regular hexagon inscribed in a circle can be divided into 6 equilateral triangles. The side length of each equilateral triangle is equal to the radius of the circle.

  • Radius of the circle, $r = 21$ cm.
  • Side length of the hexagon, $s = r = 21$ cm.

Area Formula for Hexagon

The area of a regular hexagon can be calculated using the formula:

Area = $\frac{3\sqrt{3}}{2} s^2$, where $s$ is the side length.

Calculating the Hexagon's Area

Substitute the side length ($s = 21$ cm) into the formula:

  1. Area = $\frac{3\sqrt{3}}{2} \times (21 \text{ cm})^2$
  2. Area = $\frac{3\sqrt{3}}{2} \times 441 \text{ cm}^2$
  3. Area = $\frac{1323\sqrt{3}}{2} \text{ cm}^2$

Now, using the approximate value of $\sqrt{3} \approx 1.732$:

  1. Area $\approx \frac{1323 \times 1.732}{2} \text{ cm}^2$
  2. Area $\approx \frac{2291.556}{2} \text{ cm}^2$
  3. Area $\approx 1145.778 \text{ cm}^2$

Final Approximation and Answer Choice

The calculated approximate area is $1145.778 \text{ cm}^2$. Comparing this to the given options, the closest value is 1145 $cm^2$.

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Similar Questions

  1. An L-shaped floor is made of two rectangles (6 m $\times$ 4 m and 8 m $\times$ 6 m). Tiles cost ₹450/$m^2$, but a 10% discount is given if more than 70 $m^2$ is tiled. What is the total cost after discount?
  2. A large regular polygon is made by combining 6 regular hexagons around a common center. What is the ratio of area of the combined shape to one hexagon?
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Important Questions from 2-D Mensuration

  1. The sides of a rectangular field are 169 m and 154 m long. Its area is equal to the area of a circular field. What is the circumference (in m) of the circular field? Take $\pi = \frac{22}{7}$
  2. Find the area of a sector with a central angle of 150° in a circle with a radius of 12 cm.
  3. The area of a square is $2304$ cm$^2$. Its perimeter is equal to the perimeter of a regular hexagon. What is the area (in cm$^2$) of the hexagon?
  4. Calculate the area of the triangle whose sides are 8 cm, 9 cm and 13 cm. (Rounded up to two decimal places)

  5. The length of a rectangular pitch is 30 m more than its breadth. Its area is $18,271$ m$^{2}$. Its breadth (in m) is:
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