Forum

Area Related To Circles

If  the  perimeter  of  a  circle  is  equal  to  that  of  a  square,  then  the  ratio  of  their areas  is

(A) 22 : 7 (B) 14 : 11 (C) 7 : 22 (D) 11: 14

Area Related To Circles

If the circumference of a circle and the perimeter of a square are equal, then 

(A) Area of the circle = Area of the square

(B) Area of the circle > Area of the square

(C) Area of the circle < Area of the square

(D) Nothing definite can be said about the relation between the  areas of the circle and square.

Area Related To Circles

 If the sum of the circumferences of two circles with radii R1 and R2 is equal to the

(A)  R₁ + R₂ = R  (B) R₁ + R₂ > R

(C)  R₁ + R₂ < R (D) Nothing definite can be said about the relation among R₁, R₂ and R.

Area Related To Circles

If the area of a circle is 154 cm², then its perimeter is 

(A) 11 cm (B) 22 cm (C) 44 cm (D) 55 cm

Construction

Draw a triangle ABC in which AB = 4 cm, BC = 6 cm and AC = 9 cm. Construct a triangle similar to ∆ABC with scale factor 3/2 . Justify the construction. Are   the two triangles congruent? Note that all the three angles and two sides of the two triangles are equal.

Construction

Draw  a  circle  of  radius  4  cm.  Construct  a  pair  of  tangents  to  it,  the  angle between which is 60º. Also justify the construction. Measure the distance be- tween the centre of the circle and the point of intersection of tangents.

Construction

Draw  a  triangle ABC  in  which AB  =  5  cm,  BC  =  6  cm  and  ∠ ABC = 60º . Construct  a  triangle  similar  to  ∆ ABC with  scale  factor 5/7 .  Justify  the construction.

Construction

Draw an isosceles triangle ABC in which AB = AC = 6 cm and BC = 5 cm. Construct a triangle PQR similar to  ∆ ABC in which PQ = 8 cm. Also justify the construction.

Construction

Draw two concentric circles of radii 3 cm and 5 cm. Taking a point on outer circle  construct  the  pair  of  tangents  to  the  other.  Measure  the  length  of  a tangent and verify it by actual calculation.

Construction

Draw  a  parallelogram  ABCD  in  which  BC  =  5  cm,  AB  =  3  cm  and ∠ABC  =  60°,  divide  it  into  triangles  BCD  and ABD  by  the  diagonal  BD. Construct the triangle BD’ C’ similar to ∆BDC with scale factor  4/3 . Draw the  line segment D’A’ parallel to DA where A’ lies on extended side BA. Is A’BC’D’ a parallelogram?