Home
Class 12
MATHS
If the mid-points P, Q and R of the side...

If the mid-points P, Q and R of the sides of the `Delta ABC` are `(3, 3), (3, 4) and (2,4)` respectively, then `Delta ABC` is

A

right angled

B

acute angled

C

obtuse angled

D

isosceles

Text Solution

AI Generated Solution

The correct Answer is:
To determine the type of triangle \( \Delta ABC \) given the midpoints \( P(3, 3) \), \( Q(3, 4) \), and \( R(2, 4) \), we will follow these steps: ### Step 1: Identify the midpoints and their coordinates The midpoints of the sides of triangle \( ABC \) are given as: - \( P(3, 3) \) - \( Q(3, 4) \) - \( R(2, 4) \) ### Step 2: Calculate the slopes of the sides of triangle \( PQR \) To find the slopes of the sides \( PQ \), \( PR \), and \( QR \), we will use the slope formula: \[ \text{slope} = \frac{y_2 - y_1}{x_2 - x_1} \] #### Slope of \( PQ \) Using points \( P(3, 3) \) and \( Q(3, 4) \): \[ \text{slope of } PQ = \frac{4 - 3}{3 - 3} = \frac{1}{0} \rightarrow \text{undefined (vertical line)} \] This means \( PQ \) is parallel to the y-axis. #### Slope of \( PR \) Using points \( P(3, 3) \) and \( R(2, 4) \): \[ \text{slope of } PR = \frac{4 - 3}{2 - 3} = \frac{1}{-1} = -1 \] #### Slope of \( QR \) Using points \( Q(3, 4) \) and \( R(2, 4) \): \[ \text{slope of } QR = \frac{4 - 4}{2 - 3} = \frac{0}{-1} = 0 \] This means \( QR \) is parallel to the x-axis. ### Step 3: Analyze the triangle \( PQR \) From the slopes calculated: - \( PQ \) is vertical. - \( QR \) is horizontal. Since one side is vertical and another is horizontal, triangle \( PQR \) is a right triangle. ### Step 4: Determine the lengths of the sides of triangle \( PQR \) Now, we will calculate the lengths of the sides to check if triangle \( PQR \) is isosceles. #### Length of \( PQ \) \[ PQ = \sqrt{(3 - 3)^2 + (4 - 3)^2} = \sqrt{0 + 1} = 1 \] #### Length of \( QR \) \[ QR = \sqrt{(3 - 2)^2 + (4 - 4)^2} = \sqrt{1 + 0} = 1 \] #### Length of \( PR \) \[ PR = \sqrt{(3 - 2)^2 + (4 - 3)^2} = \sqrt{1 + 1} = \sqrt{2} \] ### Step 5: Conclusion about triangle \( ABC \) Since \( PQ = QR = 1 \) and \( PR = \sqrt{2} \), two sides of triangle \( PQR \) are equal, confirming that it is an isosceles right triangle. Since \( PQR \) is a right triangle and isosceles, triangle \( ABC \) must also be a right triangle and isosceles. ### Final Answer: Triangle \( ABC \) is a right-angled isosceles triangle. ---
Promotional Banner

Similar Questions

Explore conceptually related problems

The coordinates of the mid points of the sides "BC", "CA" and "AB" of a △ ABC are (3,3), (3, 4) and (2,4) respectively. Then the triangle "ABC" is

The mid-points of the sides of a triangle are (1, 5, -1),(0,4,-2) and (2, 3, 4). Find its vertices.

If mid-points of the sides of a triangle are (1, 2, -3), (3, 0, 1) and (-1, 1, -4). Find its vertices.

Three vertices of a triangle are A (1, 2), B (-3, 6) and C(5, 4) . If D, E and F are the mid-points of the sides opposite to the vertices A, B and C, respectively, show that the area of triangle ABC is four times the area of triangle DEF.

If the coordinates of the mid-points of the sides of a triangle are (1,\ 1),\ (2,\ -3) and (3,\ 4) , find the vertices of the triangle.

In a Delta ABC the equation of the side BC is 2x-y =3 and its circumcentre and orthocentre are (2,4) and (1,2) respectively . Circumradius of Delta ABC is

In the adjoining figure D, E and F are the mid-points of the sides BC, CA and AB respectively of Delta ABC . Prove that: (i) square BDEF is a parallelogram (ii) area of Delta DEF = (1)/(4) xx " area of " Delta ABC (iii) square BDEF = (1)/(2) xx " area of " Delta ABC

If the coordinates of the mid-points of the sides of a triangle be (3,\ -2),\ (-3,\ 1) and (4,\ -3) , then find the coordinates of its vertices.

The mid-points of the sides of a triangle ABC are given by A(0, 0, 0), B(2, -1, 3) and C(4, 5, 8) Find the coordinates of A, B and C.

If the coordinates of the mid-points of the sides of a triangle are (3,4),(4,6)a n d(5,7), find its vertices.