Equilateral triangle inscribed in a circle:\nAn equilateral triangle of side 6 cm is inscribed in a circle. Find the radius of the circle.

Difficulty: Easy

Correct Answer: 2√3 cm

Explanation:


Introduction / Context:
The circumradius R of an equilateral triangle with side a is given by R = a/√3. This follows from standard geometry or from R = a/(√3) derived via central angles and chord relations.


Given Data / Assumptions:
Side a = 6 cm; the triangle is equilateral and inscribed (i.e., the circle is circumcircle).


Concept / Approach:
Apply the circumradius formula R = a/√3 directly. Keep the radical form in simplest terms to match options.


Step-by-Step Solution:

R = a/√3 = 6/√3 = (6√3)/3 = 2√3 cm.


Verification / Alternative check:
Using R = a/(√3) is equivalent to R = (a√3)/3; substituting a = 6 yields the same 2√3 cm.


Why Other Options Are Wrong:
3√2 and 4√3 are too large; √3 is half the correct value.


Common Pitfalls:
Confusing inradius r = a√3/6 with circumradius R = a/√3.


Final Answer:
2√3 cm

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