Question

An equilateral triangle of side 7 cm is inscribed in a circle then find area of circle

Answer 1

for this question i make a formula to find the area of circle inscribed in eqilateral triangle     ;;;  formulais;;→→→

tan 15×[ side ]^2

proof of formula  →→

let side of eqilateral. traingle be  a  

then ''  we know that radius of circle = area of Δ/semiprimeter  

s = a+a+a/2   = 3a/2

r = √3/4×a^2/3a/ 2    → r = side / 2√3

area of circle =  πr^2  

22/7×[a/2×1.732]^2

11/42×a^2    so,,,  11/42  = tan 15  

area of circle in equi. Δ = tan 15×a^2

your question solution is    →→↓

tan15×a^2   →→ 0.26794×7×7    →→→    13.12  cm^2