The incentre of the triangle with vertices \[\left( 1,\sqrt{3} \right),\left( 0,0 \right)\] and \[\left( 2,0 \right)\]is
\[\left( 1,\dfrac{\sqrt{3}}{2} \right)\]
\[\left( \dfrac{2}{3},\dfrac{1}{\sqrt{3}} \right)\]
\[\left( \dfrac{2}{3},\dfrac{\sqrt{3}}{2} \right)\]
\[\left( 1,\dfrac{1}{\sqrt{3}} \right)\]
.
Answer
681.9k+ views
Hint:To solve the question, we have to analyse the type of the given triangle which will result in the given triangle being an equilateral triangle. To solve further, apply the properties of the equilateral triangle, which states that the centroid and incentre of equilateral triangle coincide. To solve further, calculate the centroid of the given triangle to find the value of the incentre.
Complete Step-by-step answer:
Let the given triangle be \[\Delta ABC\]with vertices A, B, C as\[\left( 1,\sqrt{3} \right),\left( 0,0 \right)\left( 2,0 \right)\] respectively.
We know the formula for the distance between two points \[\left( {{x}_{1}},{{y}_{1}} \right),\left( {{x}_{2}},{{y}_{2}} \right)\]is given by \[\sqrt{{{\left( {{x}_{1}}-{{x}_{2}} \right)}^{2}}+{{\left( {{y}_{1}}-{{y}_{2}} \right)}^{2}}}\]
Thus, by applying the formula for the given values we get
The length of side AB =\[\sqrt{{{\left( 1-0 \right)}^{2}}+{{\left( \sqrt{3}-0 \right)}^{2}}}=\sqrt{{{1}^{2}}+{{\left( \sqrt{3} \right)}^{2}}}=\sqrt{1+3}=\sqrt{4}=2\]
\[\Rightarrow \]AB = 2 units.
The length of side BC =\[\sqrt{{{\left( 0-2 \right)}^{2}}+{{\left( 0-0 \right)}^{2}}}=\sqrt{{{\left( -2 \right)}^{2}}+{{\left( 0 \right)}^{2}}}=\sqrt{4+0}=\sqrt{4}=2\]
\[\Rightarrow \] BC = 2 units.
The length of side CA =\[\sqrt{{{\left( 1-2 \right)}^{2}}+{{\left( \sqrt{3}-0 \right)}^{2}}}=\sqrt{{{\left( -1 \right)}^{2}}+{{\left( \sqrt{3} \right)}^{2}}}=\sqrt{1+3}=\sqrt{4}=2\]
\[\Rightarrow \] CA = 2 units.
Thus, AB = BC = CA
We know that a triangle is an equilateral triangle when all the three sides of the triangle are equal.
Thus, we conclude that \[\Delta ABC\]is an equilateral triangle, as shown below:
Here D is the centroid or incentre of the given triangle.
We know that the formula for centroid of a triangle is equal to
\[\left( \dfrac{{{x}_{1}}+{{x}_{2}}+{{x}_{3}}}{3},\dfrac{{{y}_{1}}+{{y}_{2}}+{{y}_{3}}}{3} \right)\] where \[\left( {{x}_{1}},{{y}_{1}} \right),\left( {{x}_{2}},{{y}_{2}} \right)\left( {{x}_{3}},{{y}_{3}} \right)\] are vertices of a triangle.
By substituting the values in the above formula, we get
The centroid of \[\Delta ABC\]is equal to \[\left( \dfrac{1+0+2}{3},\dfrac{\sqrt{3}+0+0}{3} \right)=\left( \dfrac{3}{3},\dfrac{\sqrt{3}}{3} \right)=\left( 1,\dfrac{\sqrt{3}}{{{\left( \sqrt{3} \right)}^{2}}} \right)=\left( 1,\dfrac{1}{\sqrt{3}} \right)\]
Thus, the centroid of \[\Delta ABC\]is equal to \[\left( 1,\dfrac{1}{\sqrt{3}} \right)\]
We know that in an equilateral triangle centroid and incentre of the triangle coincidence.
Thus, the incentre of the triangle is equal to \[\left( 1,\dfrac{1}{\sqrt{3}} \right)\]
Hence, option (d) is the right choice.
Note:The possibility of mistake can be not analysing the type of the given triangle which eases the procedure of solving. The other possibility of mistake can be not applying the properties of the analysed type of triangle. The alternative way of solving the question is by using the direct formula for incentre which is equal to \[\left( \dfrac{a{{x}_{1}}+b{{x}_{2}}+c{{x}_{3}}}{a+b+c},\dfrac{a{{y}_{1}}+b{{y}_{2}}+c{{y}_{3}}}{a+b+c} \right)\]where a, b, c are the side lengths and \[\left( {{x}_{1}},{{y}_{1}} \right),\left( {{x}_{2}},{{y}_{2}} \right)\left( {{x}_{3}},{{y}_{3}} \right)\] are vertices of the given triangle.
Complete Step-by-step answer:
Let the given triangle be \[\Delta ABC\]with vertices A, B, C as\[\left( 1,\sqrt{3} \right),\left( 0,0 \right)\left( 2,0 \right)\] respectively.
We know the formula for the distance between two points \[\left( {{x}_{1}},{{y}_{1}} \right),\left( {{x}_{2}},{{y}_{2}} \right)\]is given by \[\sqrt{{{\left( {{x}_{1}}-{{x}_{2}} \right)}^{2}}+{{\left( {{y}_{1}}-{{y}_{2}} \right)}^{2}}}\]
Thus, by applying the formula for the given values we get
The length of side AB =\[\sqrt{{{\left( 1-0 \right)}^{2}}+{{\left( \sqrt{3}-0 \right)}^{2}}}=\sqrt{{{1}^{2}}+{{\left( \sqrt{3} \right)}^{2}}}=\sqrt{1+3}=\sqrt{4}=2\]
\[\Rightarrow \]AB = 2 units.
The length of side BC =\[\sqrt{{{\left( 0-2 \right)}^{2}}+{{\left( 0-0 \right)}^{2}}}=\sqrt{{{\left( -2 \right)}^{2}}+{{\left( 0 \right)}^{2}}}=\sqrt{4+0}=\sqrt{4}=2\]
\[\Rightarrow \] BC = 2 units.
The length of side CA =\[\sqrt{{{\left( 1-2 \right)}^{2}}+{{\left( \sqrt{3}-0 \right)}^{2}}}=\sqrt{{{\left( -1 \right)}^{2}}+{{\left( \sqrt{3} \right)}^{2}}}=\sqrt{1+3}=\sqrt{4}=2\]
\[\Rightarrow \] CA = 2 units.
Thus, AB = BC = CA
We know that a triangle is an equilateral triangle when all the three sides of the triangle are equal.
Thus, we conclude that \[\Delta ABC\]is an equilateral triangle, as shown below:
Here D is the centroid or incentre of the given triangle.
We know that the formula for centroid of a triangle is equal to
\[\left( \dfrac{{{x}_{1}}+{{x}_{2}}+{{x}_{3}}}{3},\dfrac{{{y}_{1}}+{{y}_{2}}+{{y}_{3}}}{3} \right)\] where \[\left( {{x}_{1}},{{y}_{1}} \right),\left( {{x}_{2}},{{y}_{2}} \right)\left( {{x}_{3}},{{y}_{3}} \right)\] are vertices of a triangle.
By substituting the values in the above formula, we get
The centroid of \[\Delta ABC\]is equal to \[\left( \dfrac{1+0+2}{3},\dfrac{\sqrt{3}+0+0}{3} \right)=\left( \dfrac{3}{3},\dfrac{\sqrt{3}}{3} \right)=\left( 1,\dfrac{\sqrt{3}}{{{\left( \sqrt{3} \right)}^{2}}} \right)=\left( 1,\dfrac{1}{\sqrt{3}} \right)\]
Thus, the centroid of \[\Delta ABC\]is equal to \[\left( 1,\dfrac{1}{\sqrt{3}} \right)\]
We know that in an equilateral triangle centroid and incentre of the triangle coincidence.
Thus, the incentre of the triangle is equal to \[\left( 1,\dfrac{1}{\sqrt{3}} \right)\]
Hence, option (d) is the right choice.
Note:The possibility of mistake can be not analysing the type of the given triangle which eases the procedure of solving. The other possibility of mistake can be not applying the properties of the analysed type of triangle. The alternative way of solving the question is by using the direct formula for incentre which is equal to \[\left( \dfrac{a{{x}_{1}}+b{{x}_{2}}+c{{x}_{3}}}{a+b+c},\dfrac{a{{y}_{1}}+b{{y}_{2}}+c{{y}_{3}}}{a+b+c} \right)\]where a, b, c are the side lengths and \[\left( {{x}_{1}},{{y}_{1}} \right),\left( {{x}_{2}},{{y}_{2}} \right)\left( {{x}_{3}},{{y}_{3}} \right)\] are vertices of the given triangle.
Recently Updated Pages
Write structures of the following compounds i 2 Chloro3methylpentane class 11 chemistry CBSE

What is BLO What is the full form of BLO class 8 social science CBSE

Explain the Treaty of Vienna of 1815 class 10 social science CBSE

A Paragraph on Pollution in about 100-150 Words

XIX+XXX A 49 B 51 C 55 D 44 class 5 maths CBSE

If x a + bt + ct2 where x is in meters and t is in class 11 physics CBSE

Trending doubts
One Metric ton is equal to kg A 10000 B 1000 C 100 class 11 physics CBSE

Draw a diagram of nephron and explain its structur class 11 biology CBSE

10 examples of friction in our daily life

Proton was discovered by A Thomson B Rutherford C Chadwick class 11 chemistry CBSE

Bond order ofO2 O2+ O2 and O22 is in order A O2 langle class 11 chemistry CBSE

Draw a labelled diagram of the neuron and describe class 11 biology CBSE

