# An equilateral triangle has a perimeter of 33 cm. What is the altitude of the triangle?

The formula for finding the altitude of an equilateral triangle is $\frac{\sqrt{3} \times s}{2}$ where $s = s i \mathrm{de}$
Since the perimeter of the triangle is $33$ and this is an equilateral triangle , we know that all 3 sides are the same length. To find $s$ (the length of a side), we divide $\frac{33}{3} = 11$
Let's plug $11$ into the equation.
$\frac{\sqrt{3} \times 11}{2}$ $\rightarrow$ $\frac{1.7321 \times 11}{2}$ $\rightarrow$ $\frac{19.0531}{2}$ $\rightarrow$ $9.52655$ $\approx$ $9.53$