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Question

In a right angled triangle, with angle at A being , the side $AB$ is of length 4cm and $BC$ is 15 cm. What is the length of side $AC$?

 

 

This question was previously asked in
RRB ALP/Technician 2018 CBT 2 Electronics Mechanic Question Paper (23-Jan-2019) (Shift 1)
The correct answer is
$\sqrt{209}\text{ cm}$

To find the length of side \( AC \) in the right-angled triangle \( \triangle ABC \), we can use the Pythagorean theorem. The Pythagorean theorem states that in a right-angled triangle, the square of the length of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the lengths of the other two sides. The theorem is given by:

\(c^2 = a^2 + b^2\)

Here, \( BC \) is the hypotenuse, \( AB = 4 \text{ cm} \), and \( BC = 15 \text{ cm} \). We need to find \( AC \).

According to the Pythagorean theorem:

\(BC^2 = AB^2 + AC^2\)

Plugging in the known values:

\((15)^2 = (4)^2 + AC^2\)

\(225 = 16 + AC^2\)

Subtracting 16 from both sides:

\(225 - 16 = AC^2\)

\(209 = AC^2\)

Taking the square root of both sides gives:

\(AC = \sqrt{209}\)

Hence, the length of side \( AC \) is \(\sqrt{209}\text{ cm}\). Therefore, the correct answer is option \(\sqrt{209}\text{ cm}\).

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Similar Questions

  1. In the given figure, if \(RS = 3\sqrt{3} \text{ cm}\) and \(RPS\) is an equilateral triangle, then find the value of \(QR\)

  2. In a right angled triangle, with angle at \(A\) being \(90^\circ\), the side \(AB\) is of length 3cm and \(BC\) is 12 cm. What is the length of side \(AC\)?
  3. For a pair of similar triangles shown in the figure, the angles made at $B$ and $R$ are same in both the triangles $BAC$ and $RAQ$. If the ratio of the areas of the two triangles is 2:1, and if the area of $BAC$ is $100\text{ cm}^2$ then what is the area of $RAQ$ in sq.cm.?

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Important Questions from Triangles

  1. What is \(AB + BC\) equal to?
     

  2. In the given figure, if \(RS = 3\sqrt{3} \text{ cm}\) and \(RPS\) is an equilateral triangle, then find the value of \(QR\)

  3. In a right angled triangle, with angle at \(A\) being \(90^\circ\), the side \(AB\) is of length 3cm and \(BC\) is 12 cm. What is the length of side \(AC\)?
  4. For a pair of similar triangles shown in the figure, the angles made at $B$ and $R$ are same in both the triangles $BAC$ and $RAQ$. If the ratio of the areas of the two triangles is 2:1, and if the area of $BAC$ is $100\text{ cm}^2$ then what is the area of $RAQ$ in sq.cm.?

  5. In a triangle $ABC$, the length of the side $AB$ is 2m, the angle at $C$ is $60^\circ$ and the angle at $B$ is $30^\circ$, what is the length of side $AC$?
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