Diameters of two internally touching circles are 7cm and 9cm distance between their centres is cm

If two circles with diameters 8 cm and 6 cm respectively touch externally, find the distance between their centers.

AB = 4cm and BC=3cm

If two circles touch externally, then the distance between their centers is the sum of their radii.

∴ distance (AC) = 4+3 = 7cm.

∴The distance between the centers= 7cm

Concept: Touching Circles

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Two circles having radii 3.5 cm and 4.8 cm touch each other internally. Find the distance between their centres.

It is given that two circle having radii 3.5 cm and 4.8 cm touch each other internally.

We know, the distance between the centres of the circles touching internally is equal to the difference of their radii.

∴ Distance between the centres of the two circles = 4.8 cm − 3.5 cm = 1.3 cm

Thus, the distance between their centres is 1.3 cm.

Let the two circles having centres P and Q touch each other internally at point R.

Here, QR = 3.5 cm, PR = 4.8 cm

The two circles touch each other internally.

By theorem of touching circles,

P − Q − R

PQ = PR − QR   ......[The distance between the centres of circles touching internally is equal to the difference in their radii]

= 4.8 – 3.5

= 1.3 cm

∴ The distance between the centres of the circles is 1.3 cm.

Concept: Touching Circles

  Is there an error in this question or solution?