11. CONSTRUCTIONS (NCERT)
NCERT
11. CONSTRUCTIONS
EXERCISE 11.1
In each of the following , give the justification of the construction also :
1. Draw a line segment of length 7.6 cm and divide it in the ratio 5 : 8 . Measure the two parts .
2. Construct a triangle of sides 4 cm , 5 cm and 6 cm and then a triangle similar to it whose sides are 
of the corresponding sides of the first triangle .
3. Construct a triangle with sides 5 cm , 6 cm and 7 cm and then another triangle whose sides are 
of the corresponding sides of the first triangle .
4. Construct an isosceles triangle whose base is 8 cm and altitude 4 cm and then another triangle whose sides are 
times the corresponding sides of the isosceles triangle .
5. Draw a triangle ABC with side 
and 
. Then construct a triangle whose sides are
of the corresponding sides of the triangle ABC .
6. Draw a triangle ABC with side 
and 
. Then, construct a triangle whose sides are 
times the corresponding sides of 
.
7. Draw a right triangle in which the sides (other than hypotenuse) are of lengths 4 cm and 3 cm . Then construct another triangle whose sides are 
times the corresponding sides of the given triangle .
EXERCISE 11.2
1. Draw a circle of radius 6 cm . From a point 10 cm away from its centre, construct the pair of tangents to the circle and measure their lengths .
2. Construct a tangent to a circle of radius 4 cm from a point on the concentric circle of radius 6 cm and measures its length . Also verify the measurement by actual calculation .
3. Draw a circle of radius 3 cm . Take two points P and Q on one of its extended diameter each at a distance of 7 cm from its centre . Draw tangents to the circle from these two points P and Q .
4. Draw a pair of tangents to a circle of radius 5 cm which are inclined to each other at an angle of 60° .
5. Draw a line segment AB of length 8 cm . Taking A as centre , draw a circle of radius 4 cm and taking B as centre, draw another circle of radius 3 cm . Construct tangents to each circle from the centre of the other circle .
6. Let ABC be a right triangle in which 
and
. BD is the perpendicular from B on AC . The circle through B , C , D is drawn . Construction the tangents from A to this circle .
7. Draw a circle with the help of a bangle . Take a point outside the circle . Construct the pair of tangents from this point to the circle .
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