Question

13. If its perimeter of an equilateral triangle is 80 cm, what will be its area?​

Answer 1

$\bold\red{\underline{\underline {Answer:}}}$

$307.77 {cm}^{2}$

$\bold\red{\underline{\underline {Step-by-step \: explanation:}}}$

Here, we are given,

▪Perimeter of a triangle = 80 cm

Hence, The sum of the three side of a triangle is = 80 cm

∴ The 1 side of the triangle is =$\frac {80}{3}$

$\begin{gathered}The \: area \: of \: the \: triangle \: is = \frac{ \sqrt{3} }{4} {a}^{2} \\ Here, \: a = 26.66 \: cm \\ ∴area = \frac{ \sqrt{3} }{4} \times (26.66)^{2} \\ \:\:\:\:\:\:\:\:\:\:\:\:\:\:= \frac{ \sqrt{3} }{4} \times 710.7556 \\ \:\:\:\:\:\:\:\:\:\:\:\:\:\:\:=sqrt{3} \times 177.6889 \\ \:\:\:\:\:\:\:\:\:\:\:\:\:\:\: = 307.77 \: {cm}^{2} \end{gathered}$

$\begin{gathered}\\\\\end{gathered}$