Question

Find the height of an equilateral triangle whose perimeter is 66cm. Hence or otherwise calculate its area.

Answer 1

Side of triangle = 66/3 = 22 cm

area of triangle = √3/4 * a² = √3/4 × 22 × 22 = 121√3 cm²

1/2 × b × h = 121√3

11 × h = 121√3

h = 11√3 Answer..

Answer 2

Answer:

perimeter

=3×side=66=>side=22 cm

therefore hieght=side×{√3/2}=11√3 cm

now area

$= \frac{1}{2} \times base \times height \\ = \frac{1}{2} \times 22 \times 11 \sqrt{3} \\ = 121 \sqrt{3} \: \: \: cm {}^{2}$