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  1. The ratio of inradius and circumradius of an equilateral triangle is :
    1. 1 : 2
    2. 2 : 1
    3. 1 : √2
    4. √2 : 1
Correct Option: A

As per the given in question , we draw a figure of an equilateral triangle with inradius and circumradius

As we know that ,

AD =
√3
× Side
2

∴ OD =
1
× AD
√3

OD =
1
×
√3a
=
a
322√3

OA =
2
AD
3

OA =
2
×
√3
a =
a
32√3

In-radius =
Side
=
a
2√32√3

Circum-radius =
Side
=
a
√3√3

∴ Required ratio =
a
:
a
= 1 : 2
2√3√3



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