Question

construct 2 tangent to a circle of radius 5 cm from an external point which is at radius 9 cm away from the centre .measure the length of the tangents . verify the measurement of the tangents. drawn by actual calculation (Pythagoras theorem)​.

Answer 1

Draw ⨀(A,5 cm) and take point B in its exterior such that AB=8 cm.

To construct:

Through B, tangents are to be drawn to ⨀(A,5 cm).

Steps of construction:

1) Draw ⨀(A,5 cm) and take point B in its exterior such that AB=8cm.

2) Draw

AB

.

3) Obtain the midpoint M of

AB

by constructing its perpendicular bisector.

4) Draw ⨀(M,MA) intersecting ⨀(A,5 cm) at X and Y.

5) Draw

BX

and

BY

.

Hence,

BX

and

BY

are the required tangents.

The length of tangents

BX

and

BY

is 6.2 (approx)

i.e., BX=BY=6.2 cm (approx.)