To this, the equilateral triangle is rotationally symmetric at a rotation of 120°or multiples of this. Let I be the incentre. It follows that R > 2r unless the two centres coincide (which only happens for an equilateral triangle). Click here to get an answer to your question ️ The area of incircle of an equilateral triangle of side 42 cm is by brainly Ankush2802 Ankush2802 07.11.2018 Math Secondary School The area of incircle of an equilateral triangle of side 42 cm is by brainly 2 See answers Always inside the triangle: The triangle's incenter is always inside the triangle. In geometry, the incircle or inscribed circle of a triangle is the largest circle contained in the triangle; it touches (is tangent to) the three sides. Let I be the incentre. Consider the triangle BIC. A circle is inscribed in the triangle if the triangle's three sides are all tangents to a circle. For Study plan details. The incircle of a triangle is the circle inscribed in the triangle. Geometry Perimeter, Area, and Volume Perimeter and Area of Triangle. Each of the triangle's three sides is a tangent to the circle. Many of these properties were simply stated by Lam? An incircle of a convex polygon is a circle which is inside the figure and tangent to each side. Become our. 2 Incircles and Excircles in a Triangle. To these, the equilateral triangle is axially symmetric. Lets see how this formula is derived, Formula to find the radius of the inscribed circle = area of the triangle / semi-perimeter of triangle. Also, let O be the centre and r be the radius of its incircle.. AB, BC and CA are tangents to the circle at M, N and P. AB = BC = CA = 9 cm 2r unless the two centres coincide (which only happens for an equilateral triangle). Another formula for the radius . ∆ABC is an equilateral triangle. Area of triangle of side a = (√3)a 2 /4. Program to calculate the Area and Perimeter of Incircle of an Equilateral Triangle. 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