Question

Find the altitude of an equilateral triangle of side $5\sqrt{3}cm$

• A. $7.5cm$
• B. $12.5cm$
• C. $9.5cm$
• D. $8.5cm$

Answer 1

The correct option is A $7.5cm$

Area of triangle = $\frac{1}{2}base\times height$

Area of equilateral triangle = $\frac{\sqrt{3}}{4}{s}^2$

Hence, $\frac{1}{2}\times s\times height=\frac{\sqrt{3}}{4}{s}^2$

$height=\frac{\sqrt{3}}{2}s$

$height=\frac{\sqrt{3}}{2}5\sqrt{3}$

$\therefore height=7.5$ cm