Answer:
MN =29 mm
Step-by-step explanation:
Two circles are there with radius 30 and 10 mm.
Common tangent has length as 21.
We have to find the distance between the centres.
If we draw a line NT parallel to PQ meeting QM at T
then we find that QTNP is a rectangle.
Hence NT=21 mm
NTM would be right triangle right angled at T, having hypotenuse as MN
one side =21 and other side = 30-10 =20
Using Pythagorean theorem,
we get
[tex]MN^{2} =21^{2} +20^{2} \\=441+400 =841\\MN =\sqrt{841} \\=29 mm[/tex]
