Q. 1 A4.4( 14 Votes )

# Let us draw the following triangles. By drawing the circum-circle in each case, let us write the position of circum-centre and the length of circum-radius by measuring it.

An equilateral triangle having each side of length 6 cm.

Answer :

Steps of Construction:

1. Construct triangle of given dimensions.

2. We name the triangle as ABC.

3. Draw perpendicular bisector of AB.

4. Draw perpendicular bisector of BC.

5. The point of intersection is the circumcenter. Name it as O.

6. With O as center and OC as radius, draw a circle.

7. The circle passes through A,B and C and is thus the circumcircle of this triangle.

8. We measure the circumradius, OC = 3.47cm.

Rate this question :

S is the centre of the circumcircle of ΔABC and if AD ⊥ BC, let us prove that ∠BAD = ∠SAC.

West Bengal Board - MathematicsLet us draw the following triangles. By drawing the circum-circle in each case, let us write the position of circum-centre and the length of circum-radius by measuring it.

ABC is triangle of which BC = 5 cm., ∠ABC = 100° and AB = 4 cm.

West Bengal Board - MathematicsLet us draw the following triangles. By drawing the circum-circle in each case, let us write the position of circum-centre and the length of circum-radius by measuring it.

right-angled triangle having length of 12 cm. hypotenuse and other side is of 5 cm length.

West Bengal Board - MathematicsO is the circumcentre of isosceles triangle ABC and ∠ABC = 120°; if the length of the radius of the circle is 5 cm, let us find the value of the side AB.

West Bengal Board - MathematicsWe draw a quadrilateral ABCD having AB = 4 cm, BC = 7 cm CD = 4 cm, ∠ABC = 60°, ∠BCD = 60°. Let us draw the circle circumscribing ΔABC and write what other characteristics we observe.

West Bengal Board - MathematicsLet us draw the following triangles. By drawing the circum-circle in each case, let us write the position of circum-centre and the length of circum-radius by measuring it.

A right-angled triangle having two sides 4 cm and 8 cm length, containing right angle.

West Bengal Board - MathematicsIf the circumcentre of triangle ABC is O; let us prove that ∠OBC + ∠BAC = 90°.

West Bengal Board - Mathematics