Question

Find the area of an equilateral triangle whose perimeter is 18cm​

Answer 1

9√3

(0r 15.58)

Explanation:

• Using Heron's formula With sides a=b=c=6 and s=9 (s=semiperimeter)

Area△=√s(s−a)(s−b)(s−c)

=√9×3×3×3

=9√3 (0r 15.58)

Answer 2

A = 15.6

Explanation:

Using the formulas

`\sf \: a = ( √(3) )/(4) {a}^(2)`

`\sf \: p = 3 \: a`

Solving for A

`\sf \: a = √(3) \frac{ {p}^(2) }{36}`

`\sf \: a \: = √(3) * \frac{ {18}^(2) }{36}`

`\sf \: a \: \approx 15.58846`