Advertisements
Advertisements
Question
Draw a line AB = 5 cm. Mark a point C on AB such that AC = 3 cm. Using a ruler and a compass only, construct:
- A circle of radius 2.5 cm, passing through A and C.
- Construct two tangents to the circle from the external point B. Measure and record the length of the tangents.
Advertisements
Solution
Steps for construction:
- Draw AB = 5 cm using a ruler.
- With A as the centre cut an arc of 3 cm on AB to obtain C.
- With A as the centre and radius 2.5 cm, draw an arc above AB.
- With same radius and C as the centre draw an arc to cut the previous arc and mark the intersection as O.
- With O as the centre and radius 2.5 cm, draw a circle so that points A and C lie on the circle formed.
- Join OB.
- Draw the perpendicular bisector of OB to obtain the mid-point of OB, M.
- With the M as the centre and radius equal to OM, draw a circle to cut the previous circle at points P and Q.
- Join PB and QB. PB and QB are the required tangents to the given circle from exterior point B.
QB = PB = 3 cm
That is, length of the tangents is 3 cm.

RELATED QUESTIONS
Draw a circle of radius 3 cm. Draw a pair of tangents to this circle, which are inclined to each other at an angle of 60º.
In the figure given below, O is the centre of the circle and SP is a tangent. If ∠SRT = 65°,
find the value of x, y and z.

Using ruler and compasses only, draw an equilateral triangle of side 4.5 cm and draw its circumscribed circle. Measure the radius of the circle.
Draw a circle with the help of a bangle. Take any point P outside the circle. Construct the pair of tangents from the point P to the circle.
Draw a pair of tangents to a circle of radius 4.5 cm, which are inclined to each other at an angle of 45°.
Draw two circles of radii 2.5 cm and 3.5 cm respectively so that their centres are 8 cm apart. Draw direct comm on tangents to the circle.
Draw a circle at a radius of 4 cm. Take a point on it. Without using the centre at the circle, draw a tangent to the circle at point P.
Draw a circle at a radius of 3 cm. Take a point at 5.5 cm from the center at the circle. From point P, draw two tangents to the circle.
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.
Construct a pair of tangents to a circle of radius 3 cm which are inclined to each other at an angle of 60°.
