Question

Two circles of radii 5.5cm and 4.2cm touch each other externally. Find the distance

between their centres.​

Answer 1

$\bigstar$Given:-

• Two circles of radii 5.5cm and 4.2cm touch each other externally

$\bigstar$To find:-

• the distance  between their centres.​

$\bigstar$Solution:-

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

Here, PQ = 5.5 cm, QR = 4.2 cm

(The circles are in the attachment)

The two circles touch each other externally.

∴ By theorem of touching circles,  

P – Q – R  

PR = PQ + QR

$\implies$5.5 + 4.2

$\implies$9.7 cm

"The distance between the centres of the circles touching externally is equal to the sum of their radii"

Therefore, the distance between their centres is "9.7cm"