Question

If $$BD, BE$$  and $$CF$$  are the medians of a $$\vartriangle ABC$$  then $$\left( {A{D^2} + B{E^2} + C{F^2}} \right):\left( {B{C^2} + C{A^2} + A{B^2}} \right)$$         is equal to

A. 4 : 3
B. 3 : 2
C. 3 : 4  
D. 2 : 3
Answer :   3 : 4
Solution :
We have, $$A{B^2} + A{C^2} = 2\left( {A{D^2} + B{D^2}} \right)$$
$$ \Rightarrow \,\,\frac{{{c^2} + {b^2}}}{2} - \frac{{{a^2}}}{4} = A{D^2},\,{\text{e}}{\text{.t}}{\text{.c}}{\text{.}}$$
Adding, $${a^2} + {b^2} + {c^2} - \frac{{{a^2} + {b^2} + {c^2}}}{4} = A{D^2} + B{E^2} + C{F^2}$$
$$ \Rightarrow \,\,\left( {A{D^2} + B{E^2} + C{F^2}} \right):\left( {{a^2} + {b^2} + {c^2}} \right) = 3:4.$$

Releted MCQ Question on
Trigonometry >> Properties and Solutons of Triangle

Releted Question 1

If the bisector of the angle $$P$$ of a triangle $$PQR$$  meets $$QR$$  in $$S,$$ then

A. $$QS = SR$$
B. $$QS : SR = PR : PQ$$
C. $$QS : SR = PQ : PR$$
D. None of these
Releted Question 2

From the top of a light-house 60 metres high with its base at the sea-level, the angle of depression of a boat is 15°. The distance of the boat from the foot of the light house is

A. $$\left( {\frac{{\sqrt 3 - 1}}{{\sqrt 3 + 1}}} \right)60\,{\text{metres}}$$
B. $$\left( {\frac{{\sqrt 3 + 1}}{{\sqrt 3 - 1}}} \right)60\,{\text{metres}}$$
C. $${\left( {\frac{{\sqrt 3 + 1}}{{\sqrt 3 - 1}}} \right)^2}{\text{metres}}$$
D. none of these
Releted Question 3

In a triangle $$ABC,$$  angle $$A$$ is greater than angle $$B.$$ If the measures of angles $$A$$ and $$B$$ satisfy the equation $$3\sin x - 4{\sin ^3}x - k = 0, 0 < k < 1,$$       then the measure of angle $$C$$ is

A. $$\frac{\pi }{3}$$
B. $$\frac{\pi }{2}$$
C. $$\frac{2\pi }{3}$$
D. $$\frac{5\pi }{6}$$
Releted Question 4

In a triangle $$ABC,$$  $$\angle B = \frac{\pi }{3}{\text{ and }}\angle C = \frac{\pi }{4}.$$     Let $$D$$ divide $$BC$$  internally in the ratio 1 : 3 then $$\frac{{\sin \angle BAD}}{{\sin \angle CAD}}$$   is equal to

A. $$\frac{1}{{\sqrt 6 }}$$
B. $${\frac{1}{3}}$$
C. $$\frac{1}{{\sqrt 3 }}$$
D. $$\sqrt {\frac{2}{3}} $$

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