Mathematics
Construct a triangle ABC with BC = 6.4 cm, CA = 5.8 cm and ∠ABC = 60°. Draw its incircle. Measure and record the radius of incircle.
Answer
Steps of construction :
Draw a line segment BC = 6.4 cm.
Cut an arc from C of 5.8 cm.
From B construct angle 60° and extend the line and mark the point A where it meets arc from C.
Join A, B and C. Hence, the △ABC is formed.
Draw the (internal) bisectors of ∠B and ∠C. Let these bisectors meet at point I.
From I, draw IN perpendicular to the side BC.
With I as centre and radius equal to IN, draw a circle. The circle so drawn touches all the sides of the △ABC, and is the required incircle of △ABC.
On measuring IN, we get the radius of the incircle.
Hence, the radius of incircle is 1.6 cm.
Related Questions
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Construct a △ABC with BC = 6.5 cm, AB = 5.5 cm, AC = 5 cm. Construct the incircle of the triangle. Measure and record the radius of the incircle.
Using ruler and compasses only :
(i) Construct a triangle ABC with the following data :
Base AB = 6 cm, AC = 5.2 cm and ∠CAB = 60°.
(ii) In the same diagram, draw a circle which passes through the points A, B and C, and mark its centre O.
Using ruler and compasses only, construct a triangle ABC in which BC = 4 cm, ∠ACB = 45° and the perpendicular from A on BC is 2.5 cm. Draw the circumcircle of triangle ABC and measure its radius.